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McDonald H, Peart J, Kurniawan ND, Galloway G, Royce SG, Samuel CS, Chen C. Hexarelin targets neuroinflammatory pathways to preserve cardiac morphology and function in a mouse model of myocardial ischemia-reperfusion. Biomed Pharmacother 2020; 127:110165. [PMID: 32403043 DOI: 10.1016/j.biopha.2020.110165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/15/2020] [Accepted: 04/13/2020] [Indexed: 11/17/2022] Open
Abstract
Acute myocardial ischemia and reperfusion injury (IRI) underly the detrimental effects of coronary heart disease on the myocardium. Despite the ongoing advances in reperfusion therapies, there remains a lack of effective therapeutic strategies for preventing IRI. Growth hormone secretagogues (GHS) have been demonstrated to improve cardiac function, attenuate inflammation and modulate the autonomic nervous system (ANS) in models of cardiovascular disease. Recently, we demonstrated a reduction in infarct size after administration of hexarelin (HEX), in a murine model of myocardial infarction. In the present study we employed a reperfused ischemic (IR) model, to determine whether HEX would continue to have a cardioprotective influence in a model of higher clinical relevance. Myocardial ischemia was induced by transient ligation of the left descending coronary artery (tLAD) in C57BL/6 J mice followed by HEX (0.3 mg/kg/day; n = 20) or vehicle (VEH) (n = 18) administration for 21 days, first administered immediately prior-to reperfusion. IR-injured and sham mice were subjected to high-field magnetic resonance imaging to assess left ventricular (LV) function, with HEX-treated mice demonstrating a significant improvement in LV function compared with VEH-treated mice. A significant decrease in interstitial collagen, TGF-β1 expression and myofibroblast differentiation was also seen in the HEX-treated mice after 21 days. HEX treatment shifted the ANS balance towards a parasympathetic predominance; combined with a significant decrease in cardiac troponin-I and TNF-α levels, these findings were suggestive of an anti-inflammatory action on the myocardium mediated via HEX. In this model of IR, HEX appeared to rebalance the deregulated ANS and activate vagal anti-inflammatory pathways to prevent adverse remodelling and LV dysfunction. There are limited interventions focusing on IRI that have been successful in improving clinical outcome in acute myocardial infarction (AMI) patients, this study provides compelling evidence towards the translational potential of HEX where all others have largely failed.
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Affiliation(s)
- H McDonald
- School of Biomedical Science, University of Queensland, Brisbane, Australia
| | - J Peart
- Menzies Health Institute of Queensland, Griffith University, Gold Coast, Australia
| | - N D Kurniawan
- Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | - G Galloway
- Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | - S G Royce
- Cardiovascular Disease Program, Biomedical Discovery Institute and Department of Pharmacology, Australia; Central Clinical School, Monash University, Victoria, Australia
| | - C S Samuel
- Cardiovascular Disease Program, Biomedical Discovery Institute and Department of Pharmacology, Australia
| | - C Chen
- School of Biomedical Science, University of Queensland, Brisbane, Australia.
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2
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Samuel CS, Royce SG, Hewitson TD, Denton KM, Cooney TE, Bennett RG. Anti-fibrotic actions of relaxin. Br J Pharmacol 2017; 174:962-976. [PMID: 27250825 PMCID: PMC5406285 DOI: 10.1111/bph.13529] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [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] [Received: 03/07/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 12/19/2022] Open
Abstract
Fibrosis refers to the hardening or scarring of tissues that usually results from aberrant wound healing in response to organ injury, and its manifestations in various organs have collectively been estimated to contribute to around 45-50% of deaths in the Western world. Despite this, there is currently no effective cure for the tissue structural and functional damage induced by fibrosis-related disorders. Relaxin meets several criteria of an effective anti-fibrotic based on its specific ability to inhibit pro-fibrotic cytokine and/or growth factor-mediated, but not normal/unstimulated, fibroblast proliferation, differentiation and matrix production. Furthermore, relaxin augments matrix degradation through its ability to up-regulate the release and activation of various matrix-degrading matrix metalloproteinases and/or being able to down-regulate tissue inhibitor of metalloproteinase activity. Relaxin can also indirectly suppress fibrosis through its other well-known (anti-inflammatory, antioxidant, anti-hypertrophic, anti-apoptotic, angiogenic, wound healing and vasodilator) properties. This review will outline the organ-specific and general anti-fibrotic significance of exogenously administered relaxin and its mechanisms of action that have been documented in various non-reproductive organs such as the cardiovascular system, kidney, lung, liver, skin and tendons. In addition, it will outline the influence of sex on relaxin's anti-fibrotic actions, highlighting its potential as an emerging anti-fibrotic therapeutic. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- C S Samuel
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of PharmacologyMonash UniversityMelbourneVic.Australia
| | - S G Royce
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of PharmacologyMonash UniversityMelbourneVic.Australia
| | - T D Hewitson
- Department of NephrologyRoyal Melbourne HospitalMelbourneVic.Australia
| | - K M Denton
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of PhysiologyMonash UniversityMelbourneVic.Australia
| | - T E Cooney
- University of Pittsburgh Medical Centre (UPMC) HamotEriePAUSA
| | - R G Bennett
- Research Service 151VA Nebraska‐Western Iowa Health Care SystemOmahaNEUSA
- Department of Internal MedicineUniversity of Nebraska Medical CenterOmahaNEUSA
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Patel KP, Giraud AS, Samuel CS, Royce SG. Combining an epithelial repair factor and anti-fibrotic with a corticosteroid offers optimal treatment for allergic airways disease. Br J Pharmacol 2016; 173:2016-29. [PMID: 27060978 DOI: 10.1111/bph.13494] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE We evaluated the extent to which individual versus combination treatments that specifically target airway epithelial damage [trefoil factor-2 (TFF2)], airway fibrosis [serelaxin (RLX)] or airway inflammation [dexamethasone (DEX)] reversed the pathogenesis of chronic allergic airways disease (AAD). EXPERIMENTAL APPROACH Following induction of ovalbumin (OVA)-induced chronic AAD in 6–8 week female Balb/c mice, animals were i.p. administered naphthalene (NA) on day 64 to induce epithelial damage, then received daily intranasal administration of RLX (0.8 mg·mL(−1)), TFF2 (0.5 mg·mL(−1)), DEX (0.5 mg·mL(−1)), RLX + TFF2 or RLX + TFF2 + DEX from days 67–74. On day 75, lung function was assessed by invasive plethysmography, before lung tissue was isolated for analyses of various measures. The control group was treated with saline + corn oil (vehicle for NA). KEY RESULTS OVA + NA-injured mice demonstrated significantly increased airway inflammation, airway remodelling (AWR) (epithelial damage/thickness; subepithelial myofibroblast differentiation, extracellular matrix accumulation and fibronectin deposition; total lung collagen concentration), and significantly reduced airway dynamic compliance (cDyn). RLX + TFF2 markedly reversed several measures of OVA + NA-induced AWR and normalized the reduction in cDyn. The combined effects of RLX + TFF2 + DEX significantly reversed peribronchial inflammation score, airway epithelial damage, subepithelial extracellular matrix accumulation/fibronectin deposition and total lung collagen concentration (by 50–90%) and also normalized the reduction of cDyn. CONCLUSIONS AND IMPLICATIONS Combining an epithelial repair factor and anti-fibrotic provides an effective means of treating the AWR and dysfunction associated with AAD/asthma and may act as an effective adjunct therapy to anti-inflammatory corticosteroids
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Affiliation(s)
- K P Patel
- Fibrosis Laboratory, Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Vic., Australia
| | - A S Giraud
- Murdoch Children's Research Institute, University of Melbourne, Vic., Australia.,Department of Paediatrics, University of Melbourne, Vic., Australia
| | - C S Samuel
- Fibrosis Laboratory, Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Vic., Australia
| | - S G Royce
- Fibrosis Laboratory, Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Vic., Australia.,Respiratory Pharmacology Laboratory, Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Vic., Australia
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Sarwar M, Samuel CS, Bathgate RA, Stewart DR, Summers RJ. Enhanced serelaxin signalling in co-cultures of human primary endothelial and smooth muscle cells. Br J Pharmacol 2016; 173:484-96. [PMID: 26493539 DOI: 10.1111/bph.13371] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In the phase III clinical trial, RELAX-AHF, serelaxin caused rapid and long-lasting haemodynamic changes. However, the cellular mechanisms involved are unclear in humans. EXPERIMENTAL APPROACH This study examined the effects of serelaxin in co-cultures of human primary endothelial cells (ECs) and smooth muscle cells (SMCs) on cAMP and cGMP signalling. KEY RESULTS Stimulation of HUVECs or human coronary artery endothelial cells (HCAECs) with serelaxin, concentration-dependently increased cGMP accumulation in co-cultured SMCs to a greater extent than in monocultures of either cell type. This was not observed in human umbilical artery endothelial cells (HUAECs) that do not express the relaxin receptor, RXFP1. Treatment of ECs with l-N(G) -nitro arginine (NOARG; 30 μM, 30 min) inhibited serelaxin-mediated (30 nM) cGMP accumulation in HUVECs, HCAECs and co-cultured SMCs. In HCAECs, but not HUVECs, pre-incubation with indomethacin (30 μM, 30 min) also inhibited cGMP accumulation in SMCs. Pre-incubation of SMCs with the guanylate cyclase inhibitor ODQ (1 μM, 30 min) had no effect on serelaxin-mediated (30 nM) cGMP accumulation in HUVECs and HCAECs but inhibited cGMP accumulation in SMCs. Serelaxin stimulation of HCAECs, but not HUVECs, increased cAMP accumulation concentration-dependently in SMCs. Pre-incubation of HCAECs with indomethacin, but not l-NOARG, abolished cAMP accumulation in co-cultured SMCs, suggesting involvement of prostanoids. CONCLUSIONS AND IMPLICATIONS In co-cultures, treatment of ECs with serelaxin caused marked cGMP accumulation in SMCs and with HCAEC also cAMP accumulation. Responses involved EC-derived NO and with HCAEC prostanoid production. Thus, serelaxin differentially modulates vascular tone in different vascular beds.
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Affiliation(s)
- M Sarwar
- Drug Discovery Biology, Monash Institute of Pharmacology, Monash University, Australia
| | - C S Samuel
- Department of Pharmacology, Monash University, Australia
| | - R A Bathgate
- The Florey Institute of Neuroscience and Mental Health and the Department of Biochemistry and Molecular Biology, University of Melbourne, Australia
| | | | - R J Summers
- Drug Discovery Biology, Monash Institute of Pharmacology, Monash University, Australia
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Sobey CG, Judkins CP, Rivera J, Lewis CV, Diep H, Lee HW, Kemp-Harper BK, Broughton BRS, Selemidis S, Gaspari TA, Samuel CS, Drummond GR. NOX1 deficiency in apolipoprotein E-knockout mice is associated with elevated plasma lipids and enhanced atherosclerosis. Free Radic Res 2015; 49:186-98. [PMID: 25496431 DOI: 10.3109/10715762.2014.992893] [Citation(s) in RCA: 27] [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] [Indexed: 11/13/2022]
Abstract
Nicotinamide adenine dinucleotide phosphate oxidases (NOX) are enzymes that generate reactive oxygen species (ROS). NOX2 activity in the vascular wall is elevated in hypercholesterolemia, and contributes to oxidative stress and atherogenesis. Here we examined the role of another NOX isoform, NOX1, in atherogenesis in apolipoprotein E-knockout (APOE(-/-)) mice fed a Western diet for 14 weeks. Although NOX1 mRNA expression was unchanged in aortas from APOE(-/-) versus wild-type mice, expression of the NOX1-specific organizer, NOXO1, was diminished, consistent with an overall reduction in NOX1 activity in APOE(-/-) mice. To examine the impact of a further reduction in NOX1 activity, APOE(-/-) mice were crossed with NOX1(-/y) mice to generate NOX1(-/y)/APOE(-/-) double-knockouts. NOX1 deficiency in APOE(-/-) mice was associated with 30-50% higher plasma very-low-density lipoprotein (VLDL)/LDL and triglyceride levels (P < 0.01). Vascular ROS levels were also elevated by twofold in NOX1(-/y)/APOE(-/-) versus APOE(-/-) mice (P < 0.05), despite no changes in expression of other NOX subunits. Although en face analysis of the descending aorta revealed no differences in plaque area between NOX1(-/y)/APOE(-/-) and APOE(-/-) mice, intimal thickening in the aortic sinus was increased by 40% (P < 0.05) in the double-knockouts. Moreover, NOX1 deficiency was associated with a less stable plaque phenotype; aortic sinus lesions contained 60% less collagen (P < 0.01), 40% less smooth muscle (P < 0.01), and 2.5-fold higher levels of matrix metalloproteinase-9 (P < 0.001) than lesions in APOE(-/-) mice. Thus, these data, which suggest a protective role for NOX1 against hyperlipidemia and atherosclerosis in APOE(-/-) mice, highlight the complex and contrasting roles of different NOX isoforms (e.g., NOX2 versus NOX1) in vascular pathology.
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Affiliation(s)
- C G Sobey
- Department of Pharmacology, Monash University , Clayton, Victoria , Australia
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Krishnan SM, Dowling JK, Ling YH, Diep H, Chan CT, Ferens D, Kett MM, Pinar A, Samuel CS, Vinh A, Arumugam TV, Hewitson TD, Kemp-Harper BK, Robertson AAB, Cooper MA, Latz E, Mansell A, Sobey CG, Drummond GR. Inflammasome activity is essential for one kidney/deoxycorticosterone acetate/salt-induced hypertension in mice. Br J Pharmacol 2015; 173:752-65. [PMID: 26103560 DOI: 10.1111/bph.13230] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 05/16/2015] [Accepted: 06/13/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Inflammasomes are multimeric complexes that facilitate caspase-1-mediated processing of the pro-inflammatory cytokines IL-1β and IL-18. Clinical hypertension is associated with renal inflammation and elevated circulating levels of IL-1β and IL-18. Therefore, we investigated whether hypertension in mice is associated with increased expression and/or activation of the inflammasome in the kidney, and if inhibition of inflammasome activity reduces BP, markers of renal inflammation and fibrosis. EXPERIMENTAL APPROACH Wild-type and inflammasome-deficient ASC(-/-) mice were uninephrectomized and received deoxycorticosterone acetate and saline to drink (1K/DOCA/salt). Control mice were uninephrectomized but received a placebo pellet and water. BP was measured by tail cuff; renal expression of inflammasome subunits and inflammatory markers was measured by real-time PCR and immunoblotting; macrophage and collagen accumulation was assessed by immunohistochemistry. KEY RESULTS 1K/DOCA/salt-induced hypertension in mice was associated with increased renal mRNA expression of inflammasome subunits NLRP3, ASC and pro-caspase-1, and the cytokine, pro-IL-1β, as well as protein levels of active caspase-1 and mature IL-1β. Following treatment with 1K/DOCA/salt, ASC(-/-) mice displayed blunted pressor responses and were also protected from increases in renal expression of IL-6, IL-17A, CCL2, ICAM-1 and VCAM-1, and accumulation of macrophages and collagen. Finally, treatment with a novel inflammasome inhibitor, MCC950, reversed hypertension in 1K/DOCA/salt-treated mice. CONCLUSIONS AND IMPLICATIONS Renal inflammation, fibrosis and elevated BP induced by 1K/DOCA/salt treatment are dependent on inflammasome activity, highlighting the inflammasome/IL-1β pathway as a potential therapeutic target in hypertension.
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Affiliation(s)
- S M Krishnan
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - J K Dowling
- Centre for Innate Immunity and Infectious Diseases, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia
| | - Y H Ling
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - H Diep
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - C T Chan
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - D Ferens
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - M M Kett
- Department of Physiology, Monash University, Clayton, Vic., Australia
| | - A Pinar
- Centre for Innate Immunity and Infectious Diseases, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia
| | - C S Samuel
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - A Vinh
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - T V Arumugam
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - T D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - B K Kemp-Harper
- Department of Pharmacology, Monash University, Clayton, Vic., Australia
| | - A A B Robertson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - M A Cooper
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - E Latz
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany.,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA.,German Center for Neurodegenerative Diseases, Bonn, Germany
| | - A Mansell
- Centre for Innate Immunity and Infectious Diseases, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia
| | - C G Sobey
- Department of Pharmacology, Monash University, Clayton, Vic., Australia.,Department of Surgery, Monash Medical Centre, Southern Clinical School, Monash University, Clayton, Vic., Australia
| | - G R Drummond
- Department of Pharmacology, Monash University, Clayton, Vic., Australia.,Department of Surgery, Monash Medical Centre, Southern Clinical School, Monash University, Clayton, Vic., Australia
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Royce SG, Lim CXF, Patel KP, Wang B, Samuel CS, Tang MLK. Intranasally administered serelaxin abrogates airway remodelling and attenuates airway hyperresponsiveness in allergic airways disease. Clin Exp Allergy 2015; 44:1399-408. [PMID: 25113628 DOI: 10.1111/cea.12391] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 03/03/2014] [Accepted: 05/08/2014] [Indexed: 01/24/2023]
Abstract
BACKGROUND The peptide hormone relaxin plays a key role in the systemic hemodynamic and renovascular adaptive changes that occur during pregnancy, which is linked to its antiremodelling effects. Serelaxin (a recombinant form of human gene-2 relaxin) has been shown to inhibit lung fibrosis in various disease models and reverse airway remodelling and airway hyperresponsiveness (AHR) in allergic airways disease (AAD). OBJECTIVE Although continuous systemic delivery of exogenous serelaxin alleviates allergic fibrosis and AHR, more direct routes for administration into the lung have not been investigated. Thus, intranasal administration of serelaxin was evaluated for its ability to reverse airway remodelling and AHR associated with AAD. METHODS Female Balb/c mice were subjected to a 9-week model of chronic AAD. Subgroups of animals (n = 12/group) were then treated intranasally with serelaxin (0.8 mg/mL) or vehicle once daily for 14 days (from weeks 9-11). Saline-sensitized/challenged mice treated with intranasal saline served as additional controls. Differential bronchoalveolar lavage (BAL) cell counts, ovalbumin (OVA)-specific IgE levels, tissue inflammation, parameters of airway remodelling and AHR were then assessed. RESULTS Chronic AAD was associated with significant increases in differential BAL cell counts, OVA-specific IgE levels, inflammation, epithelial thickening, goblet cell metaplasia, TGF-β1 expression, epithelial Smad2 phosphorylation (pSmad2), subepithelial collagen thickness, total lung collagen concentration and AHR (all P < 0.05 vs. respective measurements from saline-treated mice). Daily intranasal delivery of serelaxin significantly diminished AAD-induced epithelial thickening, epithelial pSmad2, subepithelial and total lung collagen content (fibrosis) and AHR (all P < 0.05 vs. vehicle-treated AAD mice). CONCLUSIONS AND CLINICAL RELEVANCE Intranasal delivery of serelaxin can effectively reduce airway remodelling and AHR, when administered once daily. Respirable preparations of serelaxin may have therapeutic potential for the prevention and/or reversal of established airway remodelling and AHR in asthma.
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Affiliation(s)
- S G Royce
- Allergy and Immune Disorders, Murdoch Children's Research Institute, Melbourne, Vic., Australia; Department of Pharmacology, Monash University, Melbourne, Vic., Australia
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Tilak M, Paul A, Samuel CS, David JA, Viswabandya A, Srivastava A. Cryotherapy for acute haemarthrosis in haemophilia - attempts to understand the ‘ice age’ practice. Haemophilia 2014; 21:e103-5. [DOI: 10.1111/hae.12581] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2014] [Indexed: 12/28/2022]
Affiliation(s)
- M. Tilak
- Department of Physical Medicine and Rehabilitation; Christian Medical College; Vellore India
| | - A. Paul
- Department of Physical Medicine and Rehabilitation; Christian Medical College; Vellore India
| | - C. S. Samuel
- Department of Physical Medicine and Rehabilitation; Christian Medical College; Vellore India
| | - J. A. David
- Department of Physical Medicine and Rehabilitation; Christian Medical College; Vellore India
| | | | - A. Srivastava
- Haematology; Christian Medical College; Vellore India
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Sarwar M, Samuel CS, Bathgate RA, Stewart DR, Summers RJ. Serelaxin-mediated signal transduction in human vascular cells: bell-shaped concentration-response curves reflect differential coupling to G proteins. Br J Pharmacol 2014; 172:1005-19. [PMID: 25297987 DOI: 10.1111/bph.12964] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 09/16/2014] [Accepted: 09/24/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE In a recently conducted phase III clinical trial, RELAX-AHF, serelaxin infusion over 48 h improved short- and long-term clinical outcomes in patients with acute heart failure. In this study we used human primary cells from the umbilical vasculature to better understand the signalling mechanisms activated by serelaxin. EXPERIMENTAL APPROACH We examined the acute effects of serelaxin on signal transduction mechanisms in primary human umbilical vascular cells and its chronic actions on markers of cardiovascular function and disease. KEY RESULTS The RXFP1 receptor, the cognate serelaxin receptor, was expressed at the cell surface in HUVECs and human umbilical vein smooth muscle cells (HUVSMCs), human umbilical artery smooth muscle cells (HUASMCs) and human cardiac fibroblasts (HCFs), but not human umbilical artery endothelial cells. In HUVECs and HUVSMCs, serelaxin increased cAMP, cGMP accumulation and pERK1/2, and the concentration-response curves (CRCs) were bell-shaped. Similar bell-shaped CRCs for cGMP and pERK1/2 were observed in HCFs, whereas in HUASMCs, serelaxin increased cAMP, cGMP and pERK1/2 with sigmoidal CRCs. Gαi/o and lipid raft disruption, but not Gαs inhibition, altered the serelaxin CRC for cAMP and cGMP accumulation in HUVSMC but not HUASMC. Longer term serelaxin exposure increased the expression of neuronal NOS, VEGF, ETβ receptors and MMPs (gelatinases) in RXFP1 receptor-expressing cells. CONCLUSIONS AND IMPLICATIONS Serelaxin caused acute and chronic changes in human umbilical vascular cells that were cell background dependent. Bell-shaped CRCs that were observed only in venous cells and fibroblasts involved Gαi/o located within membrane lipid rafts.
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Affiliation(s)
- M Sarwar
- Drug Discovery Biology, Monash Institute of Pharmacology, Monash University, Melbourne, Vic., Australia
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Yong KL, Callander GE, Bergin R, Samuel CS, Bathgate RAD. Development of human cells with RXFP1 knockdown using retroviral delivery of microRNA against human RXFP1. Ital J Anat Embryol 2013; 118:10-12. [PMID: 24640558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To study the specific actions of relaxin through RXFP1 in human cells, it would be advantageous to develop cell populations with permanent RXFP1 knockdown (KD). We have developed and assessed four microRNA against human RXFP1. One of the four designed microRNA displayed significant RXFP1 KD as assessed by reduced relaxin binding when co-transfected with human RXFP1 into HEK-293T cells. The selected microRNA sequence was subsequently retrovirally delivered into the human dermal fibroblast cell line BJ3 which natively expresses RXFP1. The RXFP1 KD BJ3 cells displayed diminished RXFP1 mRNA expression and complete loss of ability of relaxin treatment to reduce collagen deposition after TGF-beta1 stimulation. The retroviral expression of miRNA to successfully silence RXFP1 expression is an invaluable tool to investigate receptor specificity, signalling and possible off-target effects of newly developed relaxin analogs.
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Bathgate RAD, Lekgabe ED, McGuane JT, Su Y, Pham T, Ferraro T, Layfield S, Hannan RD, Thomas WG, Samuel CS, Du XJ. Adenovirus-mediated delivery of relaxin reverses cardiac fibrosis. Mol Cell Endocrinol 2008; 280:30-8. [PMID: 17961912 DOI: 10.1016/j.mce.2007.09.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [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] [Received: 06/20/2007] [Revised: 09/07/2007] [Accepted: 09/12/2007] [Indexed: 11/16/2022]
Abstract
We have evaluated the effectiveness of systemic adenovirally delivered mouse relaxin on reversing fibrosis in a transgenic murine model of fibrotic cardiomyopathy due to beta(2)-adrenergic receptor (beta(2)AR) overexpression. Recombinant adenoviruses expressing green fluorescent protein (Ad-GFP), rat relaxin (Ad-rRLN) and mouse relaxin (Ad-mRLN) were generated and Ad-rRLN and Ad-mRLN were demonstrated to direct the expression of bioactive relaxin peptides in vitro. A single systemic injection of Ad-mRLN resulted in transgene expression in the liver and bioactive relaxin peptide in the plasma. Ad-mRLN, but not Ad-GFP, treatment reversed the increased left ventricular collagen content in beta(2)AR mice to control levels without affecting collagen levels in other heart chambers or in the lung and kidney. Hence a single systemic injection of adenovirus producing mouse relaxin reverses cardiac fibrosis without adversely affecting normal collagen levels in other organs and establishes the potential for the use of relaxin gene therapy for the treatment of cardiac fibrosis.
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Affiliation(s)
- R A D Bathgate
- Howard Florey Institute, University of Melbourne, Victoria 3010, Australia.
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Abstract
The peptide hormone relaxin is emerging as a multi-functional factor in a broad range of target tissues including several non-reproductive organs, in addition to its historical role as a hormone of pregnancy. This review discusses the evidence that collectively demonstrates the many diverse and vital roles of relaxin: the homeostatic role of endogenous relaxin in mammalian pregnancy and ageing; its gender-related effects; the therapeutic effects of relaxin in the treatment of fibrosis, inflammation, cardioprotection, vasodilation and wound healing (angiogenesis) amongst other pathophysiological conditions, and its potential mechanism of action. Furthermore, translational issues using experimental models (to humans) and its use in various clinical trials, are described, each with important lessons for the design of future trials involving relaxin. The diverse physiological and pathological roles for relaxin have led to the search for its significance in humans and highlight its potential as a drug of the future.
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Affiliation(s)
- C S Samuel
- Howard Florey Institute and Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.
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Abstract
Fibrosis (organ scarring) is a hallmark of many forms of cardiovascular and renal disease, and causes organ dysfunction and structural changes when normal tissue is replaced with scar tissue; the accumulation of scar tissue being a leading cause of death around the world. Despite deep organ scarring potentially existing in many forms (including myocardial and vascular sclerosis, renal interstitial fibrosis, and glomerulosclerosis), current therapies have only had limited success in delaying end-stage disease. The peptide hormone relaxin is emerging as a potent antifibrotic therapy with rapid-occurring efficacy. Recent studies have demonstrated the antifibrotic actions of relaxin in experimental models of cardiac and renal disease in vivo, and the various levels at which relaxin acts to inhibit fibroblast-induced collagen overproduction leading to fibrosis, in vitro. Separate studies using relaxin gene-knockout mice have demonstrated the significance of endogenous relaxin as a naturally occurring and protective moderator of collagen turnover, while the therapeutic potential of relaxin has been enhanced by its ability to promote vasodilation and renal hyperfiltration. This review will summarize these coherent findings as a means of highlighting the clinical potential of relaxin in cardiovascular and renal disease.
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Affiliation(s)
- C S Samuel
- Howard Florey Institute of Experimental Physiology and Medicine, The University of Melbourne, Parkville, Victoria, Australia.
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14
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Fu P, Shen PJ, Zhao CX, Scott DJ, Samuel CS, Wade JD, Tregear GW, Bathgate RAD, Gundlach AL. Leucine-rich repeat-containing G-protein-coupled receptor 8 in mature glomeruli of developing and adult rat kidney and inhibition by insulin-like peptide-3 of glomerular cell proliferation. J Endocrinol 2006; 189:397-408. [PMID: 16648305 DOI: 10.1677/joe.1.06697] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [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: 11/27/2022]
Abstract
Leucine-rich repeat-containing G-protein-coupled receptor 8 (LGR8, or RXFP2) is a member of the type C leucine-rich repeat-containing G protein-coupled receptor family, and its endogenous ligand is insulin-like peptide-3 (INSL3). Although LGR8 expression has been demonstrated in various human tissues, including testis, ovary, brain and kidney, the precise roles of this receptor in many of these tissues are unknown. In an effort to better understand INSL3-LGR8 systems in the rat, we cloned the full-length Lgr8 cDNA and investigated the presence and cellular localization of Lgr8 mRNA expression in adult and developing rat kidney. On the basis of these findings, we investigated the presence and distribution of renal 125I-labelled human INSL3-binding sites and the nature of INSL3-LGR8 signalling in cultured renal cells. Thus, using in situ hybridization histochemistry, cells expressing Lgr8 mRNA were observed in glomeruli of renal cortex from adult rats and were tentatively identified as mesangial cells. Quantitative, real-time PCR analysis of the developmental profile of Lgr8 mRNA expression in kidney revealed highest relative levels at late stage gestation (embryonic day 18), with a sharp decrease after birth and lowest levels in the adult. During development, silver grains associated with Lgr8 mRNA hybridization were observed overlying putative mesangial cells in mature glomeruli, with little or no signal associated with less-mature glomeruli. In adult and developing kidney, specific 125I-INSL3-binding sites were associated with glomeruli throughout the renal cortex. In primary cultures of glomerular cells, synthetic human INSL3 specifically and dose-dependently inhibited cell proliferation over a 48 h period, further suggesting the presence of functional LGR8 (receptors) on these cells (mesangial and others). These findings suggest INSL3-LGR8 signalling may be involved in the genesis and/or developmental maturation of renal glomeruli and possibly in regulating mesangial cell density in adult rat kidney.
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Affiliation(s)
- P Fu
- Howard Florey Institute, The University of Melbourne, Victoria 3010, Australia
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15
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Wintour EM, Moritz KM, Johnson K, Ricardo S, Samuel CS, Dodic M. Reduced nephron number in adult sheep, hypertensive as a result of prenatal glucocorticoid treatment. J Physiol 2003; 549:929-35. [PMID: 12730337 PMCID: PMC2342989 DOI: 10.1113/jphysiol.2003.042408] [Citation(s) in RCA: 179] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/27/2003] [Accepted: 03/27/2003] [Indexed: 11/08/2022] Open
Abstract
There is some evidence, mainly from rodent studies, that any factor which alters the final total number of nephrons formed, during nephrogenesis, will result in hypertension in adult life. Sheep, programmed to become hypertensive by exposure to synthetic glucocorticoid (dexamethasone, 0.48 mg h-1, for 48 h) early in development (~27 days of gestation), were killed at 7 years of age, and had nephron counting performed by unbiased stereology. Mean arterial pressure was 83 +/- 4 mmHg in the dexamethasone (DEX) group (n = 5), and 73 +/- 5 in the control (CON; n = 7; P < 0.05). The total nephron number, in the right kidney (249 070 +/- 14 331; n = 5) was significantly lower (P < 0.01) than that of controls (402 787 +/- 30 458; n = 7). Mean glomerular volume was larger in the DEX than the CON group (P < 0.01), but there was no significant difference in the sclerosis index between the two groups. Low nephron number was associated with grossly enlarged and dilated proximal tubules and greater accumulation of collagen type I and type III in the tubular interstitium and periadventitia of the renal cortical vessels. These data suggest that the hypertensive programming effect of glucocorticoid treatment, early in kidney development, results, at least in part, from impaired nephrogenesis.
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Affiliation(s)
- E M Wintour
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville 3010, Victoria, Australia.
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16
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Abstract
The relaxin knockout (rlx -/-) mouse was used to assess the effect, during pregnancy, of relaxin with regard to water, collagen content, growth, and morphology of the nipple (N), vagina (V), uterus, cervix (C), pubic symphysis (PS), and mammary gland (MG). The results presented here indicate that during pregnancy, relaxin increases the growth of the N, C, V, and PS. Large increases in water content in the PS (20%) occurred in pregnant (Day 18.5) wild-type (rlx +/+) mice but not in rlx -/- animals. This indicates that in the PS, relaxin might increase the concentration of a water-retaining extracellular matrix component (hyaluronate). In the pregnant rlx +/+ mouse, collagen content decreased significantly in the N and V but not in other tissues. There were no significant changes in the rlx -/- mouse. This contrasts with findings in the rat, in which relaxin has been found to cause decreases in collagen concentrations in the V, C, and PS. Histological analysis showed that the collagen stain was more condensed in the tissues (V, C, PS, N, and MG) of rlx -/- mice than in those of rlx +/+ mice. This phenomenon indicates that the failure of collagen degradation and lack of growth in the N underlie the inability of the rlx -/- mice to feed their young, as reported previously. Vaginal and cervical luminal epithelia, which proliferated markedly in the rlx +/+ pregnant mice, remained relatively atrophic in the rlx -/- mice. As proliferation and differentiation of uterine and vaginal epithelia are thought to be induced by a paracrine stromal factor that acts upon estrogen stimulation, our results indicate that relaxin may be this paracrine factor.
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Affiliation(s)
- L Zhao
- Howard Florey Institute of Experimental Physiology and Medicine, The University of Melbourne, Parkville, Victoria 3010, Australia
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17
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Abstract
The aim of this study was to examine the changes in collagen metabolism that occur during pregnancy and parturition and upon relaxin administration to the rat pubic symphysial interpubic tissue. Pubic symphyses were collected from non-pregnant, and intact and ovariectomised pregnant Sprague-Dawley rats at days 15, 18 and 21 of pregnancy as well as during and after delivery, and analysed for collagen content and solubility. SDS-PAGE was used to determine collagen composition. During pregnancy and particularly during birth, there was a significant reduction in both the tissue wet (57+/-3%) and dry (43+/-3%) weight (n=7), which coincided with a significant increase in water content (to 80%) and was attributed to a significant (P<0.05) reduction in overall tissue collagen content (by 47+/-2%). This resulted in both soluble (10%) and insoluble (90%) collagen levels being reduced, but gel electrophoresis demonstrated the presence of types I, II and V collagen in all samples. Western blot analysis confirmed the presence of type II collagen throughout pregnancy, confirming that the rat pubic symphysis remained a fibrocartilaginous tissue throughout gestation. In the absence of the ovaries and hence relaxin, tissue collagen content and solubility were not significantly different from control measurements. However, tissues of ovariectomised animals treated with oestrogen and progesterone (pellets) and relaxin (injection) contained collagen levels that mimicked those of late pregnancy and parturition. These results suggest that relaxin plays an important role in regulating collagen catabolism during gestation in the rat.
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Affiliation(s)
- C S Samuel
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Australia
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18
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Shandley L, Moritz KM, Samuel CS, Wintour EM. Collagen in the fetal membranes of sheep: changes throughout gestation and effects of dexamethasone at 60 days. Reprod Fertil Dev 1997; 9:455-64. [PMID: 9402256 DOI: 10.1071/r96103] [Citation(s) in RCA: 3] [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: 02/05/2023] Open
Abstract
The tensile strength of fetal membranes is largely due to their collagen content. In this study we have examined the changes in collagen in the amniotic and allantoic membranes of the sheep over a wide gestational range (27-142 days of gestation; term, 145-150 days). The results have been correlated with volume changes in normal development, and in particular, the changes in allantois have been studied after a rapid and extensive increase in allantoic volume, as a result of maternal dexamethasone treatment (0.76 mg h-1 for 48 h) from Day 60 of gestation. Electron microscopy and immunohistochemistry were used to delineate collagen distribution, and gel electrophoresis was used to assess the relative proportions of each type. In the amnion, collagen content increased from 37 +/- 4% to 50 +/- 1% dry weight of the tissue from 41-102 days and declined slightly thereafter. In the allantois, collagen content increased from 20 +/- 1% at Day 27 to 50 +/- 6% at Day 142, significantly correlated with a volume increase from 25 +/- 3 mL to 813 +/- 274 mL. Collagen types I (>85%), III (10%) and small amounts of types IV and V (<5%) were identified in both membranes at all ages. When allantoic fluid volume was increased rapidly by maternal dexamethasone infusion, there was a significant decrease in collagen content from 38 +/- 6% to 25 +/- 2% (P < 0.05). By immunohistochemistry it was observed that both epithelial cells and fibroblasts were synthesizing collagen.
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Affiliation(s)
- L Shandley
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Australia
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Samuel CS, Butkus A, Coghlan JP, Bateman JF. The effect of relaxin on collagen metabolism in the nonpregnant rat pubic symphysis: the influence of estrogen and progesterone in regulating relaxin activity. Endocrinology 1996; 137:3884-90. [PMID: 8756561 DOI: 10.1210/endo.137.9.8756561] [Citation(s) in RCA: 75] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The aim of this study was to examine the effects of relaxin on collagen content, solubility, and composition in the rat pubic symphysis. Nonpregnant, female Sprague-Dawley rats were bilaterally ovariectomized and either unprimed or primed with estrogen or progesterone alone, or a combination of estrogen and progesterone. One week later these animals were given increasing doses of a synthetic human (gene-2) relaxin (0-100 micrograms) before being killed 16 h later. Their pubic symphysial tissues were then removed and analyzed for collagen content and solubility, whereas collagen composition was determined by SDS-PAGE. Relaxin administration significantly increased the length (140 +/- 6%) and weight (170 +/- 9%) of the interpubic fibrocartilage in estrogen-primed rats (n = 15). At the same time, it decreased the total collagen content by 68 +/- 6%, without altering the proportions of collagen types, which were predominantly type I (85%) and type II collagen (15%). Relaxin administered alone reduced the total collagen content by 64 +/- 4% but had no effect on collagen solubility or composition. Progesterone abolished the effects of relaxin in estrogen-primed rats. It is concluded that relaxin has a potent effect on the amount of collagen in the rat pubic symphysis that is enhanced by estrogen and antagonized by progesterone. The changes in the extracellular matrix within the pubic symphysis induced by relaxin may be important in the modifications that this tissue undergoes during pregnancy.
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Affiliation(s)
- C S Samuel
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Australia
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Ahamed RN, Mummigatti UG, Samuel CS. Effect of adrenalectomy and administration of prednisolone on gastric ulcer formation in forestomachectomized Shay albino rats. Indian J Physiol Pharmacol 1983; 27:298-304. [PMID: 6430799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The gastric ulcerogenic effect of the glucocorticoid, prednisolone, was studied in albino rats. Shay operation in forestomachectomized rats with intact adrenals induced acute gastric ulcers in the corpus, whereas adrenalectomy prevented the development of gastric ulcers in another group of forestomachectomized Shay rats. Only superficial erosion of gastric epithelium was noticed in 66.67% of these rats. Administration of prednisolone to another group of similarly operated rats increased the number and severity of gastric ulceration, whether the adrenals were ablated or otherwise. From the observation of acid and mucous content of the stomach, it is postulated that the reduced mucous secretion may be an important predisposing factor in gastric ulcerogenic effect of steroids.
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