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Kanai A, Chakrabarty B, Winder M, Hashim H, Wein A, Abrams P, Fry C. New therapeutic targets to prevent benign prostatic enlargement and symptomatic progression to benign prostatic obstruction-ICI-RS 2023. Neurourol Urodyn 2024; 43:1363-1371. [PMID: 37916442 PMCID: PMC11063119 DOI: 10.1002/nau.25326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 10/24/2023] [Indexed: 11/03/2023]
Abstract
AIMS Benign prostatic enlargement (BPE) can impact lower urinary tract function due to its potential progression to benign prostatic obstruction (BPO). Treatment options include removal of the obstruction by surgery or through use of therapeutics designed to slow growth or reduce tissue stress imposed by muscular stromal components. Inflammation and development of fibrosis can also raise intrinsic tissue stress within the gland, further impacting obstruction. Outflow tract obstruction can also impact emission and ejaculation if the obstruction persists. METHODS This review summarizes an ICI-RS think tank considering novel drug treatments that might address BPO caused by progressive development of BPE, as well as manage decompensation changes to bladder function. RESULTS Topics included recent advances in our understanding of pathological changes occurring to the prostate and other lower urinary tract tissues during progressive development of BPE, and how prevention or reversal might benefit from the identification of novel drug targets. These included contractile properties of prostatic tissues, the impact of BPE and its effects on bladder function, the deposition of intramural fibrotic tissue with protracted BPO, the role of inflammation in the development of BPE and its progression to BPO. In particular, we discussed current therapeutic options for treating BPE/BPO, and new therapeutic targets, what they treat and their advantage over current medications. CONCLUSION Several new drug targets were identified, including soluble guanylate cyclase (sGC), the receptor for nitric oxide (NO•), and sGC activators that promotes sGC-mediated cGMP production when sGC is inactivated and unresponsive to NO•.
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Affiliation(s)
- Anthony Kanai
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, US
- Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, US
| | - Basu Chakrabarty
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Michael Winder
- Department of Pharmacology, University of Gothenburg, Gothenburg, SE
| | - Hashim Hashim
- Bristol Urological Institute, North Bristol NHS Trust, Bristol, UK
| | - Alan Wein
- Desai Sethi Institute of Urology, University of Miami Miller School of Medicine, Miami, Florida, US
| | - Paul Abrams
- Bristol Urological Institute, North Bristol NHS Trust, Bristol, UK
| | - Christopher Fry
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
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Badshah M, Ibrahim J, Su N, Whiley P, Whittaker M, Exintaris B. The Effects of Age on Prostatic Responses to Oxytocin and the Effects of Antagonists. Biomedicines 2023; 11:2956. [PMID: 38001957 PMCID: PMC10669827 DOI: 10.3390/biomedicines11112956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
Benign prostatic hyperplasia (BPH) is an age-related enlargement of the prostate with urethral obstruction that predominantly affects the middle-aged and older male population, resulting in disruptive lower urinary tract symptoms (LUTS), thus creating a profound impact on an individual's quality of life. The development of LUTS may be linked to overexpression of oxytocin receptors (OXTR), resulting in increased baseline myogenic tone within the prostate. Thus, it is hypothesised that targeting OXTR using oxytocin receptor antagonists (atosiban, cligosiban, and β-Mercapto-β,β-cyclopentamethylenepropionyl1, O-Me-Tyr2, Orn8]-Oxytocin (ßMßßC)), may attenuate myogenic tone within the prostate. Organ bath and immunohistochemistry techniques were conducted on prostate tissue from young and older rats. Our contractility studies demonstrated that atosiban significantly decreased the frequency of spontaneous contractions within the prostate of young rats (**** p < 0.0001), and cligosiban (* p < 0.05), and ßMßßC (**** p < 0.0001) in older rats. Additionally, immunohistochemistry findings revealed that nuclear-specific OXTR was predominantly expressed within the epithelium of the prostate of both young (*** p < 0.001) and older rats (**** p < 0.0001). In conclusion, our findings indicate that oxytocin is a key modulator of prostate contractility, and targeting OXTR is a promising avenue in the development of novel BPH drugs.
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Affiliation(s)
- Masroor Badshah
- Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia;
| | - Jibriil Ibrahim
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, VIC 3052, Australia (N.S.)
| | - Nguok Su
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, VIC 3052, Australia (N.S.)
| | - Penny Whiley
- Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168, Australia;
| | - Michael Whittaker
- Drug, Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, VIC 3052, Australia;
| | - Betty Exintaris
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, VIC 3052, Australia (N.S.)
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3
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Lee SN, Kraska J, Papargiris M, Teng L, Niranjan B, Hammar J, Ryan A, Frydenberg M, Lawrentschuk N, Middendorff R, Ellem SJ, Whittaker M, Risbridger GP, Exintaris B. Oxytocin receptor antagonists as a novel pharmacological agent for reducing smooth muscle tone in the human prostate. Sci Rep 2021; 11:6352. [PMID: 33737570 PMCID: PMC7973579 DOI: 10.1038/s41598-021-85439-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/22/2021] [Indexed: 11/09/2022] Open
Abstract
Pharmacotherapies for the treatment of Benign Prostatic Hyperplasia (BPH) are targeted at reducing cellular proliferation (static component) or reducing smooth muscle tone (dynamic component), but response is unpredictable and many patients fail to respond. An impediment to identifying novel pharmacotherapies is the incomplete understanding of paracrine signalling. Oxytocin has been highlighted as a potential paracrine mediator of BPH. To better understand oxytocin signalling, we investigated the effects of exogenous oxytocin on both stromal cell proliferation, and inherent spontaneous prostate contractions using primary models derived from human prostate tissue. We show that the Oxytocin Receptor (OXTR) is widely expressed in the human prostate, and co-localises to contractile cells within the prostate stroma. Exogenous oxytocin did not modulate prostatic fibroblast proliferation, but did significantly (p < 0.05) upregulate the frequency of spontaneous contractions in prostate tissue, indicating a role in generating smooth muscle tone. Application of atosiban, an OXTR antagonist, significantly (p < 0.05) reduced spontaneous contractions. Individual tissue responsiveness to both exogenous oxytocin (R2 = 0.697, p < 0.01) and atosiban (R2 = 0.472, p < 0.05) was greater in tissue collected from older men. Overall, our data suggest that oxytocin is a key regulator of inherent spontaneous prostate contractions, and targeting of the OXTR and associated downstream signalling is an attractive prospect in the development of novel BPH pharmacotherapies.
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Affiliation(s)
- Sophie N Lee
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Jenna Kraska
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,TissuPath, Melbourne, VIC, Australia
| | - Melissa Papargiris
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,TissuPath, Melbourne, VIC, Australia
| | - Linda Teng
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Birunthi Niranjan
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Johanna Hammar
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | | | - Mark Frydenberg
- Department of Surgery, Monash University, Melbourne, VIC, Australia.,Australian Urology Associates, Melbourne, VIC, Australia
| | - Nathan Lawrentschuk
- Department of Surgery, Austin Health, University of Melbourne, Melbourne, VIC, Australia.,EJ Whitten Prostate Cancer Research Centre at Epworth Heathcare, Melbourne, Australia
| | - Ralf Middendorff
- Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Stuart J Ellem
- School of Health and Wellbeing, Faculty of Health, Engineering and Sciences, University of Southern Queensland, Ipswich, QLD, Australia
| | - Michael Whittaker
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Faculty of Pharmacy and Pharmaceutical Sciences, Parkville, VIC, Australia
| | - Gail P Risbridger
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Betty Exintaris
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia.
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Chakrabarty B, Lee S, Exintaris B. Generation and Regulation of Spontaneous Contractions in the Prostate. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:195-215. [PMID: 31183828 DOI: 10.1007/978-981-13-5895-1_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Spontaneous myogenic contractions have been shown to be significantly upregulated in prostate tissue collected from men with Benign Prostatic Hyperplasia (BPH), an extremely common disorder of the ageing male. Although originally thought likely to be involved in 'housekeeping' functions, mixing prostatic secretions to prevent stagnation, these spontaneous myogenic contractions provide a novel opportunity to understand and treat BPH. This treatment potential differs from previous models, which focused exclusively on attenuating nerve-mediated neurogenic contractions. Previous studies in the rodent prostate have provided an insight into the mechanisms underlying the regulation of myogenic contractions. 'Prostatic Interstitial Cells' (PICs) within the prostate appear to generate pacemaker potentials, which arise from the summation of number of spontaneous transient depolarisations triggered by the spontaneous release of Ca2+ from internal stores and the opening of Ca2+-activated Cl- channels. Pacemaker potentials then conduct into neighbouring smooth muscle cells to generate spontaneous slow waves. These slow waves trigger the firing of 'spike-like' action potentials, Ca2+ entry and contraction, which are not attenuated by blockers of neurotransmission. However, these spontaneous prostatic contractions can be modulated by the autonomic nervous system. Here, we discuss the mechanisms underlying rodent and human prostate myogenic contractions and the actions of existing and novel pharmacotherapies for the treatment of BPH. Understanding the generation of human prostatic smooth muscle tone will confirm the mechanism of action of existing drugs, inform the identification and effectiveness of new pharmacotherapies, as well as predict patient outcomes.
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Affiliation(s)
- Basu Chakrabarty
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Melbourne, VIC, Australia
| | - Sophie Lee
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Melbourne, VIC, Australia
| | - Betty Exintaris
- Drug Discovery Biology, Monash Institute of Pharmaceutical Science, Melbourne, VIC, Australia.
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Abstract
The prostate is a gland whose secretions contribute to the seminal fluids ejaculated upon
activation of autonomic sympathetic nerves. In elder males, the prostate undergoes an
increase in stroma mass and myogenic tone, leading to benign prostatic hyperplasia that
occludes the proximal urethra and the presentation of various lower urinary tract symptoms
that decrease their quality of life. This review summarises the role of prostatic
interstitial cells (PICs) in the generation of the spontaneous tone in the prostate. It
presents current knowledge of the role of Ca2+ plays in PIC pacemaking, as well as the
mechanisms by which this spontaneous activity triggers slow wave generation and stromal
contraction. PICs display a small T-type Ca2+ current (ICaT) and a large L-type Ca2+
current (ICaL). In contrast to other interstitial cells in the urinary and
gastrointestinal tracts, spontaneous Ca2+ signalling in PICs is uniquely dependent on Ca2+
influx through ICaL channels. A model of prostatic pacemaking is presented describing how
ICaL can be triggered by an initial membrane depolarization evoked upon the selective
opening of Ca2+-activated Cl– channels by Ca2+ flowing only through ICaT channels. The
resulting current flow through ICaL results in release of Ca2+ from internal stores and
the summation of Cl–-selective spontaneous transient depolarizations (STDs) to form
pacemaker potentials that propagate passively into the prostatic stroma to evoke
regenerative action potentials and excitation-contraction coupling.
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Affiliation(s)
- Richard J Lang
- Department of Physiology, School of Biomedical Sciences, Monash University, Clayton Victoria 3800, Australia
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
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Age Related Differences in Responsiveness to Sildenafil and Tamsulosin are due to Myogenic Smooth Muscle Tone in the Human Prostate. Sci Rep 2017; 7:10150. [PMID: 28860509 PMCID: PMC5578961 DOI: 10.1038/s41598-017-07861-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/03/2017] [Indexed: 11/08/2022] Open
Abstract
Lower urinary tract symptoms (LUTS) due to Benign Prostatic Hyperplasia (BPH) are highly prevalent in older men, having a profound impact on patient quality of life. Current therapeutics for BPH/LUTS target neurogenic smooth muscle tone, but response is unpredictable and many patients fail to respond. Spontaneous myogenic tone is another component of smooth muscle contractility that is uncharacterized in human prostate. To better understand and improve the predictability of patient response, we defined myogenic contractility using human prostate specimens and examined the effect of existing therapeutics. We show that myogenic activity is present in the human prostate with the frequency of contractions in transition zone (TZ) specimens from BPH diagnosed patients approximately 160% greater than matched controls. α1-adrenoreceptor antagonists (Tamsulosin) and PDE5 inhibitors (Sildenafil) both significantly reduced myogenic contractile parameters, including frequency, with notable interpatient variability. Tamsulosin was more effective in older patients (R2 = 0.36, p < 0.01) and men with larger prostate volumes (R2 = 0.41, p < 0.05), while Sildenafil was more effective in younger men (R2 = 0.45, p < 0.05). As myogenic tone is significantly increased in BPH, therapeutics targeting this mechanism used with reference to patient characteristics could improve clinical outcomes and better predict patient response.
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Kirpatovskii VI, Mudraya IS, Revenko SV, Bablumyan AY, Adamyan NK, Ivanov VP. Effect of Doxazosin on Autonomic Nervous Control and Urodynamics of Rat Urinary Bladder during Modeled Infravesical Obstruction. Bull Exp Biol Med 2016; 161:657-661. [PMID: 27709382 DOI: 10.1007/s10517-016-3479-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Indexed: 11/26/2022]
Abstract
The therapeutic effect of doxazosin (40 μg/kg/day over one month) on urinary bladder was examined in female rats with modeled chronic infravesical obstruction (IVO) produced by graduated mechanical constriction of the proximal urethral segment. In one month, IVO induced a pronounced vesical hypertrophy both in treated and untreated rats that manifested in increased bladder weight and capacity, the latter increment being pronouncedly greater in treated rats. In untreated IVO rats, infusion cystometry revealed elevated basal intravesical pressure of void bladder P0, markedly increased maximal (premicturitional) pressure Pmax, and increased amplitude of spontaneous oscillations of intravesical pressure ΔPdet in filled bladder. Doxazosin produced no significant effect on Pmax rise during IVO, but prevented elevation of P0 and increment of ΔPdet in filled bladder. During gradual filling of urinary bladder in control (intact) rats, the parasympathetic vesical influences increased progressively, while in untreated IVO rats, the adrenergic influences prevailed even at maximal filling of the bladder. In IVO rats, doxazosin prevented the bias of the sympathetic-parasympathetic balance in the filled bladder in favor of sympathetic influences, but did not prevent this bias in a void bladder. It is hypothesized that α-adrenoblockers improve micturition during IVO caused by benign prostatic hyperplasia not only by decreasing the urethral resistance to urine flow due to down-regulation of prostate smooth muscle tone, but also by a direct action of these blockers on detrusor adrenergic receptors and central structures involved in urinary bladder control.
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Affiliation(s)
- V I Kirpatovskii
- Department of Experimental Modeling of Urological Diseases, N. Lopatkin Research Institute of Urology - Affiliated Branch of National Medical Research Radiology Centre, Ministry of Health of the Russian Federation, Moscow, Russia.
| | - I S Mudraya
- Department of Experimental Modeling of Urological Diseases, N. Lopatkin Research Institute of Urology - Affiliated Branch of National Medical Research Radiology Centre, Ministry of Health of the Russian Federation, Moscow, Russia
| | - S V Revenko
- Department of Experimental Modeling of Urological Diseases, N. Lopatkin Research Institute of Urology - Affiliated Branch of National Medical Research Radiology Centre, Ministry of Health of the Russian Federation, Moscow, Russia
| | - A Yu Bablumyan
- Department of Experimental Modeling of Urological Diseases, N. Lopatkin Research Institute of Urology - Affiliated Branch of National Medical Research Radiology Centre, Ministry of Health of the Russian Federation, Moscow, Russia
| | - N K Adamyan
- Department of Experimental Modeling of Urological Diseases, N. Lopatkin Research Institute of Urology - Affiliated Branch of National Medical Research Radiology Centre, Ministry of Health of the Russian Federation, Moscow, Russia
| | - V P Ivanov
- Department of Experimental Modeling of Urological Diseases, N. Lopatkin Research Institute of Urology - Affiliated Branch of National Medical Research Radiology Centre, Ministry of Health of the Russian Federation, Moscow, Russia
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Calcium signalling in Cajal-like interstitial cells of the lower urinary tract. Nat Rev Urol 2014; 11:555-64. [PMID: 25224445 DOI: 10.1038/nrurol.2014.241] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Interstitial cells of Cajal (ICC) serve several critical physiological roles in visceral smooth muscle organs, including acting as electrical pacemakers to modulate phasic contractile activity and as intermediaries in motor neurotransmission. The major roles of ICC have been described in the gastrointestinal tract, however, ICC-like cells (ICC-LC) can also be found in other visceral organs, including those of the lower urinary tract (LUT), where they provide similar functions, acting as electrical pacemakers and as intermediary cells involved in the modulation of neurotransmission to adjacent smooth muscle cells. The physiological functions of ICC-LC, in particular their role as pacemakers, relies on their ability to generate transient and propagating intracellular Ca(2+) events. The role of ICC-LC as pacemakers and neuromodulators in the LUT is increasingly apparent and the study of their intracellular Ca(2+) dynamics will provide a better understanding of their role in LUT excitability.
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