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Pereira DA, Calmasini FB, Costa FF, Burnett AL, Silva FH. Nitric Oxide Resistance in Priapism Associated with Sickle Cell Disease: Mechanisms, Therapeutic Challenges, and Future Directions. J Pharmacol Exp Ther 2024; 390:203-212. [PMID: 38262744 DOI: 10.1124/jpet.123.001962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/07/2023] [Accepted: 01/05/2024] [Indexed: 01/25/2024] Open
Abstract
Patients with sickle cell disease (SCD) display priapism, a prolonged penile erection in the absence of sexual arousal. The current pharmacological treatments for SCD-associated priapism are limited and focused on acute interventions rather than prevention. Thus, there is an urgent need for new drug targets and preventive pharmacological therapies for this condition. This review focuses on the molecular mechanisms linked to the dysfunction of the NO-cyclic guanosine monophosphate (cGMP)-phosphodiesterase type 5 (PDE5) pathway implicated in SCD-associated priapism. In murine models of SCD, reduced nitric oxide (NO)-cGMP bioavailability in the corpus cavernosum is associated with elevated plasma hemoglobin levels, increased reactive oxygen species levels that inactive NO, and testosterone deficiency that leads to endothelial nitric oxide synthase downregulation. We discuss the consequences of the reduced cGMP-dependent PDE5 activity in response to these molecular changes, highlighting it as the primary pathophysiological mechanism leading to excessive corpus cavernosum relaxation, culminating in priapism. We also further discuss the impact of intravascular hemolysis on therapeutic approaches, present current pharmacological strategies targeting the NO-cGMP-PDE5 pathway in the penis, and identify potential pharmacological targets for future priapism therapies. In men with SCD and priapism, PDE5 inhibitor therapy and testosterone replacement have shown promising results. Recent preclinical research reported the beneficial effect of treatment with haptoglobin and NO donors. SIGNIFICANCE STATEMENT: This review discusses the molecular changes that reduce NO-cGMP bioavailability in the penis in SCD and highlights pharmacological targets and therapeutic strategies for the treatment of priapism, including PDE5 inhibitors, hormonal modulators, NO donors, hydroxyurea, soluble guanylate cyclase stimulators, haptoglobin, hemopexin, and antioxidants.
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Affiliation(s)
- Dalila Andrade Pereira
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil (D.A.P., F.H.S.); Universidade Federal de São Paulo, Escola Paulista de Medicina, Department of Pharmacology, São Paulo, SP, Brazil (F.B.C.); Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil (F.F.C.); and The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland (A.L.B.)
| | - Fabiano Beraldi Calmasini
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil (D.A.P., F.H.S.); Universidade Federal de São Paulo, Escola Paulista de Medicina, Department of Pharmacology, São Paulo, SP, Brazil (F.B.C.); Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil (F.F.C.); and The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland (A.L.B.)
| | - Fernando Ferreira Costa
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil (D.A.P., F.H.S.); Universidade Federal de São Paulo, Escola Paulista de Medicina, Department of Pharmacology, São Paulo, SP, Brazil (F.B.C.); Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil (F.F.C.); and The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland (A.L.B.)
| | - Arthur L Burnett
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil (D.A.P., F.H.S.); Universidade Federal de São Paulo, Escola Paulista de Medicina, Department of Pharmacology, São Paulo, SP, Brazil (F.B.C.); Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil (F.F.C.); and The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland (A.L.B.)
| | - Fábio Henrique Silva
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil (D.A.P., F.H.S.); Universidade Federal de São Paulo, Escola Paulista de Medicina, Department of Pharmacology, São Paulo, SP, Brazil (F.B.C.); Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil (F.F.C.); and The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland (A.L.B.)
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Pereira DA, Silveira THR, Calmasini FB, Silva FH. Soluble guanylate cyclase stimulators and activators: new horizons in the treatment of priapism associated with sickle cell disease. Front Pharmacol 2024; 15:1357176. [PMID: 38384294 PMCID: PMC10879333 DOI: 10.3389/fphar.2024.1357176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 01/25/2024] [Indexed: 02/23/2024] Open
Abstract
Priapism, defined as a prolonged and often painful penile erection occurring without sexual stimulation or desire, is a common complication in sickle cell disease (SCD), affecting up to 48% of male patients. This condition presents significant clinical challenges and can lead to erectile dysfunction if not properly managed. Current pharmacological treatments for SCD-related priapism are primarily reactive rather than preventative, highlighting a gap in effective medical intervention strategies. A critical factor in developing priapism is the reduced basal bioavailability of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) in erectile tissues. New prevention strategies should ideally target the underlying pathophysiology of the disease. Compounds that stimulate and activate soluble guanylate cyclase (sGC) emerge as potential therapeutic candidates since these compounds have the property of inducing cGMP production by sGC. This review explores the potential of sGC stimulators and activators in treating priapism associated with SCD. We discuss the advantages of these agents in the face of the challenging pathophysiology of SCD. Additionally, the review underscores the impact of intravascular hemolysis and oxidative stress on priapism pathophysiology in SCD, areas in which sGC stimulators and activators may also have beneficial therapeutic effects.
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Affiliation(s)
- Dalila Andrade Pereira
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil
| | | | - Fabiano Beraldi Calmasini
- Department of Pharmacology, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, SP, Brazil
| | - Fábio Henrique Silva
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, SP, Brazil
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Gül M, Luca B, Dimitropoulos K, Capogrosso P, Milenkovic U, Cocci A, Veeratterapillay R, Hatzichristodoulou G, Modgil V, Russo GI, Tharakan T, Kalkanli A, Omar MI, Bettocchi C, Carvalho J, Corona G, Jones TH, Kadioglu A, Martinez-Salamanca JI, Serefoglu EC, Verze P, Minhas S, Salonia A. What is the effectiveness of surgical and non-surgical therapies in the treatment of ischemic priapism in patients with sickle cell disease? A systematic review by the EAU Sexual and Reproductive Health Guidelines Panel. Int J Impot Res 2024; 36:20-35. [PMID: 35941221 DOI: 10.1038/s41443-022-00590-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/09/2022]
Abstract
Sickle cell disease (SCD) is an inherited hemoglobin disorder characterized by the occlusion of small blood vessels by sickle-shaped red blood cells. SCD is associated with a number of complications, including ischemic priapism. While SCD accounts for at least one-third of all priapism cases, no definitive treatment strategy has been established to specifically treat patients with SC priapism. The aim of this systematic review was to assess the efficacy and safety of contemporary treatment modalities for acute and stuttering ischemic priapism associated with SCD. The primary outcome measures were defined as resolution of acute priapism (detumescence) and complete response of stuttering priapism, while the primary harm outcome was as sexual dysfunction. The protocol for the review has been registered (PROSPERO Nr: CRD42020182001), and a systematic search of Medline, Embase, and Cochrane controlled trials databases was performed. Three trials with 41 observational studies met the criteria for inclusion in this review. None of the trials assessed detumescence, as a primary outcome. All of the trials reported a complete response of stuttering priapism; however, the certainty of the evidence was low. It is clear that assessing the effectiveness of specific interventions for priapism in SCD, well-designed, adequately-powered, multicenter trials are strongly required.
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Affiliation(s)
- M Gül
- Department of Urology, Selcuk University School of Medicine, Urology, Konya, Turkey
| | - B Luca
- Urological Research Institute, IRCCS Ospedale San Raffaele, Experimental Oncology/Unit of Urology, Milan, Italy
| | | | - P Capogrosso
- ASST-Sette Laghi, Circolo & Fondazione Macchi Hospital, University of Insurbria, Varese, Italy
| | - U Milenkovic
- University of Leuven, Laboratory for Experimental Urology, Leuven, Belgium
| | - A Cocci
- Careggi Hospital, University of Florence, Urology, Florence, Italy
| | - R Veeratterapillay
- Freeman Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Urology, Newcastle, UK
| | - G Hatzichristodoulou
- Julius-Maximilians-University of Würzburg, Urology and Pediatric Urology, Würzburg, Germany
| | - V Modgil
- Manchester Royal Infirmary, Manchester University Hospitals NHS Foundation Trust, Manchester Andrology Centre, Manchester, UK
| | - G I Russo
- Vittorio Emanuele II, University of Catania, Urology, Catania, Italy
| | - T Tharakan
- Charing Cross Hospital, Imperial College Healthcare NHS Trust, Urology, London, UK
| | - A Kalkanli
- Taksim Education and Research Hospital, Department of Urology, Istanbul, Turkey
| | - M I Omar
- University of Aberdeen, Academic Urology Unit, Aberdeen, UK
| | - C Bettocchi
- University of Foggia, Department of Urology, Foggia, Italy
| | - J Carvalho
- Lusófona University of Humanities and Technologies, School of Psychology and Life Sciences, Lisbon, Portugal
| | - G Corona
- Azienda Usl Bologna Maggiore-Bellaria Hospital, Endocrinology Unit, Bologna, Italy
| | - T H Jones
- University of Sheffield Medical School, Oncology and Metabolism, Sheffield, UK
| | - A Kadioglu
- Istanbul University, Urology, Istanbul, Turkey
| | | | | | - P Verze
- University of Naples Federico II, Urology, Naples, Italy
| | - S Minhas
- Imperial Healthcare NHS Trust, Charing Cross Hospital, Urology, London, UK
| | - A Salonia
- URI-Urological Research Institute, Experimental Oncology/Unit of Urology, Milan, Italy.
- University Vita-salute San Raffaele, Milan, Italy.
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Pereira DA, Pereira DA, Silveira THR, Calmasini FB, Burnett AL, Costa FF, Silva FH. Heme-induced corpus cavernosum relaxation and its implications for priapism in sickle cell disease: a mechanistic insight. Andrology 2024. [PMID: 38231174 DOI: 10.1111/andr.13599] [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: 09/26/2023] [Revised: 12/15/2023] [Accepted: 01/08/2024] [Indexed: 01/18/2024]
Abstract
BACKGROUND Patients with sickle cell disease (SCD) experience intravascular hemolysis, leading to elevated plasma heme levels. This phenomenon has been associated with increased priapism in men with SCD. The heme group can be metabolized by heme oxygenase (HO), generating carbon monoxide (CO), which is known to promote smooth muscle relaxation via soluble guanylyl cyclase (sGC)-cyclic guanosine monophosphate (cGMP). However, the effects of heme on the relaxation responses of corpus cavernosum (CC) have not been investigated. OBJECTIVES To evaluate the functional and biochemical effects of the heme group on mouse CC smooth muscle in vitro. MATERIALS AND METHODS Male C57BL/6 mice were used. CC tissues were mounted in organ baths. Measurement of cGMP in mice CC was evaluated. RESULTS The cumulative addition of heme concentrations promoted the relaxation of CC. HO inhibitor (1J, 100 μM) or sGC inhibitor (ODQ, 10 μM) blocked the relaxing effect of the heme group. Pre-incubation of CC with heme (100 μM) enhanced relaxation induced by acetylcholine, sodium nitroprusside, and nitrergic relaxation (electrical field stimulation), which was abolished by 1J or ODQ. The heme group increased the cGMP production in CC, which was abolished by 1J or ODQ. cGMP levels were significantly higher in CC treated with heme, and pre-incubation with compound 1J or ODQ abolished the effect of heme in raising cGMP levels. DISCUSSION AND CONCLUSION The HO-CO-sGC-cGMP pathway appears to play a crucial role in promoting CC relaxation. Our study provides novel insight into the role of group heme in CC relaxation and its potential contribution to priapism in SCD. Heme may serve as a pharmacological target for new therapies to prevent priapism.
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Affiliation(s)
- Dalila Andrade Pereira
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, São Paulo, SP, Brazil
| | - Danillo Andrade Pereira
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, São Paulo, SP, Brazil
| | | | - Fabiano Beraldi Calmasini
- Department of Pharmacology, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, SP, Brazil
| | - Arthur L Burnett
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | | | - Fábio Henrique Silva
- Laboratory of Pharmacology, São Francisco University Medical School, Bragança Paulista, São Paulo, SP, Brazil
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Kamimura S, Smith M, Vogel S, Almeida LEF, Thein SL, Quezado ZMN. Mouse models of sickle cell disease: Imperfect and yet very informative. Blood Cells Mol Dis 2024; 104:102776. [PMID: 37391346 PMCID: PMC10725515 DOI: 10.1016/j.bcmd.2023.102776] [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: 05/31/2023] [Accepted: 06/16/2023] [Indexed: 07/02/2023]
Abstract
The root cause of sickle cell disease (SCD) has been known for nearly a century, however, few therapies to treat the disease are available. Over several decades of work, with advances in gene editing technology and after several iterations of mice with differing genotype/phenotype relationships, researchers have developed humanized SCD mouse models. However, while a large body of preclinical studies has led to huge gains in basic science knowledge about SCD in mice, this knowledge has not led to the development of effective therapies to treat SCD-related complications in humans, thus leading to frustration with the paucity of translational progress in the SCD field. The use of mouse models to study human diseases is based on the genetic and phenotypic similarities between mouse and humans (face validity). The Berkeley and Townes SCD mice express only human globin chains and no mouse hemoglobin. With this genetic composition, these models present many phenotypic similarities, but also significant discrepancies that should be considered when interpreting preclinical studies results. Reviewing genetic and phenotypic similarities and discrepancies and examining studies that have translated to humans and those that have not, offer a better perspective of construct, face, and predictive validities of humanized SCD mouse models.
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Affiliation(s)
- Sayuri Kamimura
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Meghann Smith
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sebastian Vogel
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Luis E F Almeida
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Swee Lay Thein
- Sickle Cell Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zenaide M N Quezado
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA; Sickle Cell Branch, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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de Oliveira MG, Passos GR, de Gomes EDT, Leonardi GR, Zapparoli A, Antunes E, Mónica FZ. Inhibition of multidrug resistance proteins by MK571 restored the erectile function in obese mice through cGMP accumulation. Andrology 2023; 11:611-620. [PMID: 36375168 DOI: 10.1111/andr.13340] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 09/09/2022] [Accepted: 11/06/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Intracellular levels of cyclic nucleotides can also be controlled by the action of multidrug resistance protein types 4 (MRP4) and 5 (MRP5). To date, no studies evaluated the role of their inhibition in an animal model of erectile dysfunction (ED). OBJECTIVES To evaluate the effect of a 2-week treatment with MK571, an inhibitor of the efflux of cyclic nucleotides in the ED of obese mice. MATERIALS AND METHODS Mice were divided in three groups: (i) lean, (ii) obese, and (iii) obese + MK571. The corpus cavernosum (CC) were isolated, and concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), and tadalafil in addition to electrical field stimulation (EFS) were carried out in phenylephrine pre-contracted tissues. Expression of ABCC4 and ABCC5, intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), the protein levels for pVASPSer157 and pVASPSer239 , and the intracavernous pressure (ICP) were also determined. The intracellular and extracellular (supernatant) ratios in CC from obese and lean stimulated with a cGMP-increasing substance (BAY 58-2667) in the absence and presence of MK571 (20 μM, 30 min) were also assessed. RESULTS The treatment with MK571 completely reversed the lower relaxing responses induced by EFS, ACh, SNP, and tadalafil observed in obese mice CC in comparison with untreated obese mice. Cyclic GMP and p-VASPSer239 expression were significantly reduced in CC from obese groups. MK571 promoted a sixfold increase in cGMP without interfering in the protein expression of p-VASPSer239 . Neither the cAMP levels nor p-VASPSer157 were altered in MK571-treated animals. The ICP was ∼50% lower in obese than in the lean mice; however, the treatment with MK571 fully reversed this response. Expressions of ABCC4 and ABCC5 were not different between groups. The intra/extracellular ratio of cGMP was similar in CC from obese and lean mice stimulated with BAY 58-2667. CONCLUSIONS The MRPs inhibition by MK571 favored the accumulation of cGMP in the smooth muscle cells, thus improving the smooth muscle relaxation and the erectile function in obese mice.
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Affiliation(s)
- Mariana Gonçalves de Oliveira
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Gabriela Reolon Passos
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Erick de Toledo de Gomes
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Guilherme Ruiz Leonardi
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Adriana Zapparoli
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Edson Antunes
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Fabiola Zakia Mónica
- Department of Translation Medicine (Pharmacology area), Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
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Iacopucci APM, da Silva Pereira P, Pereira DA, Calmasini FB, Pittalà V, Reis LO, Burnett AL, Costa FF, Silva FH. Intravascular hemolysis leads to exaggerated corpus cavernosum relaxation: Implication for priapism in sickle cell disease. FASEB J 2022; 36:e22535. [PMID: 36070139 DOI: 10.1096/fj.202200867r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/17/2022] [Accepted: 08/24/2022] [Indexed: 11/11/2022]
Abstract
Patients with sickle cell disease (SCD) display priapism. Clinical studies have shown a strong positive correlation between priapism and high levels of intravascular hemolysis in men with SCD. However, there are no experimental studies that show that intravascular hemolysis promotes alterations in erectile function. Therefore, we aimed to evaluate the corpus cavernosum smooth muscle relaxant function in a murine model that displays intravascular hemolysis induced by phenylhydrazine (PHZ), as well as the role of intravascular hemolysis in increasing the stress oxidative in the penis. Corpus cavernosum strips were dissected free and placed in organ baths. Acetylcholine and electrical field stimulation (EFS)-induced corpus cavernosum relaxations in vitro were obtained. Increased corpus cavernosum relaxant responses to acetylcholine and EFS were observed in the PHZ group. Protein expression of heme oxygenase-1 increased in the corpus cavernosum of the PHZ group, but PDE5 protein expression was not modified. Preincubation with the heme oxygenase inhibitor 1 J completely reversed the increased relaxant responses to acetylcholine and EFS in PHZ mice. Protein expression of NADPH oxidase subunit gp91phox, 3-nitrotyrosine, and 4-hydroxynonenal increased in the corpus cavernosum of the PHZ group, suggesting a state of oxidative stress. Basal cGMP production was lower in the PHZ group. Our results show that intravascular hemolysis promotes increased corpus cavernosum smooth muscle relaxation associated with increased HO-1 expression, as well as increased oxidative stress associated with upregulation of gp91phox expression. Moreover, our study supports clinical studies that point to a strong positive correlation between priapism and high levels of intravascular hemolysis in men with SCD.
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Affiliation(s)
- Ana Paula Magrini Iacopucci
- Laboratory of Multidisciplinary Research, São Francisco University Medical School, Bragança Paulista, Brazil
| | | | - Dalila Andrade Pereira
- Laboratory of Multidisciplinary Research, São Francisco University Medical School, Bragança Paulista, Brazil
| | - Fabiano Beraldi Calmasini
- Laboratory of Multidisciplinary Research, São Francisco University Medical School, Bragança Paulista, Brazil
| | - Valeria Pittalà
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | | | - Arthur L Burnett
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | | | - Fábio Henrique Silva
- Laboratory of Multidisciplinary Research, São Francisco University Medical School, Bragança Paulista, Brazil
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Musicki B, Burnett AL. Testosterone Deficiency in Sickle Cell Disease: Recognition and Remediation. Front Endocrinol (Lausanne) 2022; 13:892184. [PMID: 35592776 PMCID: PMC9113536 DOI: 10.3389/fendo.2022.892184] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/31/2022] [Indexed: 11/30/2022] Open
Abstract
Hypogonadism is common in men with sickle cell disease (SCD) with prevalence rates as high as 25%. Testicular failure (primary hypogonadism) is established as the principal cause for this hormonal abnormality, although secondary hypogonadism and compensated hypogonadism have also been observed. The underlying mechanism for primary hypogonadism was elucidated in a mouse model of SCD, and involves increased NADPH oxidase-derived oxidative stress in the testis, which reduces protein expression of a steroidogenic acute regulatory protein and cholesterol transport to the mitochondria in Leydig cells. In all men including those with SCD, hypogonadism affects physical growth and development, cognition and mental health, sexual function, as well as fertility. However, it is not understood whether declines in physical, psychological, and social domains of health in SCD patients are related to low testosterone, or are consequences of other abnormalities of SCD. Priapism is one of only a few complications of SCD that has been studied in the context of hypogonadism. In this pathologic condition of prolonged penile erection in the absence of sexual excitement or stimulation, hypogonadism exacerbates already impaired endothelial nitric oxide synthase/cGMP/phosphodiesterase-5 molecular signaling in the penis. While exogenous testosterone alleviates priapism, it disadvantageously decreases intratesticular testosterone production. In contrast to treatment with exogenous testosterone, a novel approach is to target the mechanisms of testosterone deficiency in the SCD testis to drive endogenous testosterone production, which potentially decreases further oxidative stress and damage in the testis, and preserves sperm quality. Stimulation of translocator protein within the transduceosome of the testis of SCD mice reverses both hypogonadism and priapism, without affecting intratesticular testosterone production and consequently fertility. Ongoing research is needed to define and develop therapies that restore endogenous testosterone production in a physiologic, mechanism-specific fashion without affecting fertility in SCD men.
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Joice GA, Liu JL, Burnett AL. Medical treatment of recurrent ischaemic priapism: a review of current molecular therapeutics and a new clinical management paradigm. BJU Int 2021; 127:498-506. [PMID: 33606327 DOI: 10.1111/bju.15370] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES To examine the current molecular therapeutics in the medical treatment of recurrent ischemic priapism (RIP). To propose a stepwise clinical management paradigm for the treatment of RIP. METHODS We performed a literature search using the PubMed database for the terms 'recurrent ischemic priapism' and 'stuttering priapism' up until December 2020. We assessed pre-clinical and clinical studies regarding medical management of RIP and molecular pathophysiology. Case series and randomized trials were evaluated by study quality and patient outcomes to determine a potential clinical management scheme. RESULTS Recent research has fostered an improved understanding of the underlying molecular pathophysiology of RIP that has paved the way forward for developing new therapeutic agents. Medications targeting neurovascular, hormonal and haematological mechanisms associated with RIP show great promise towards remedying this condition. A host of therapeutic agents operating across different mechanistic directions may be implemented according to a clinical management scheme to potentially optimize RIP outcomes. CONCLUSION RIP remains a medically neglected condition with current management focused on treating the acute condition rather than modulating the course of disease. Continued research into the molecular mechanisms of RIP and standardized clinical pathways can improve the quality of care for patients suffering from this condition.
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Affiliation(s)
- Gregory A Joice
- James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - James L Liu
- James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Arthur L Burnett
- James Buchanan Brady Urological Institute and Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Musicki B, Burnett AL. Mechanisms underlying priapism in sickle cell disease: targeting and key innovations on the preclinical landscape. Expert Opin Ther Targets 2020; 24:439-450. [PMID: 32191546 DOI: 10.1080/14728222.2020.1745188] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Introduction: Priapism is prolonged penile erection in the absence of sexual arousal or desire and is a devastating condition affecting millions of patients with sickle cell disease (SCD) globally. Available drug treatments for SCD-related priapism remain limited and have been primarily reactive rather than preventive. Hence, there is an unmet need for new drug targets and pharmacologic therapies.Areas covered: We examine the molecular mechanisms underlying SCD-associated priapism evaluated mostly in animal models. In mouse models of SCD, molecular defects of priapism operating at the cavernous tissue level include reduced tonic NO/cGMP signaling, elevated oxidative/nitrosative stress, vascular adhesion molecule derangements, excessive adenosine and opiorphin signaling, dysregulated vasoconstrictive RhoA/ROCK signaling, and testosterone deficiency. We discuss the consequences of downregulated cGMP-dependent phosphodiesterase type 5 (PDE5) activity in response to these molecular signaling derangements, as the main effector mechanism causing unrestrained cavernous tissue relaxation that results in priapism.Expert opinion: Basic science studies are crucial for understanding the underlying pathophysiology of SCD-associated priapism. Understanding the molecular mechanisms could unearth new therapeutic targets for this condition based on these mechanisms. Treatment options should aim to improve deranged erection physiology regulatory signaling to prevent priapism and potentially restore or preserve erectile function.
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Affiliation(s)
- Biljana Musicki
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Arthur L Burnett
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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11
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Burnett AL. Rare disorders of penile erection. Fertil Steril 2020; 113:6-12. [DOI: 10.1016/j.fertnstert.2019.11.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/12/2019] [Indexed: 12/11/2022]
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Greenwald MH, Gutman CK, Morris CR. Resolution of Acute Priapism in Two Children With Sickle Cell Disease Who Received Nitrous Oxide. Acad Emerg Med 2019; 26:1102-1105. [PMID: 31228879 DOI: 10.1111/acem.13822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Nitrous oxide (N O) is an inhalational medication that has anxiolytic, amnestic, potent venodilatory and mild-to-moderate analgesic properties commonly used in the emergency department (ED) setting. N2 O has a rapid onset of action (<5 minutes) and recovery (<5 minutes) and can be quickly titrated to effect without the need for IV access. It has few side effects, does not require renal or hepatic metabolism for excretion and has no reports of allergic reaction. Priapism is a serious complication of sickle cell disease (SCD) affecting approximately 35% of males, with an adverse impact on quality of life. Treatment options are limited and not evidence based, including hydration, alkalization, analgesia, oxygenation to prevent further sickling, and exchange transfusion. Patients who do not respond within 4 hours often require a painful invasive procedure that includes aspiration of blood from the corpus cavernosum and phenylephrine injections. Case reports have described a therapeutic benefit from oral pseudoephedrine, sildenafil, and intravenous (IV) arginine, however controlled clinical trials are lacking. Although a 50:50 nitrous oxide/oxygen mix is commonly used in France to enhance analgesia in patients with SCD and vasoocclusive pain events (VOE) not sufficiently responding to IV morphine, there are no reports of its use to treat priapism. We describe the effects of N2 O for the treatment of acute priapism associated with SCD in a pediatric ED. METHODS This is a case series of two adolescent boys with Hb-SS who on 3 separate occasions presented to the ED with acute priapism that failed oral therapy (pseudoephedrine and opioids). N2 O gas was utilized to help facilitate IV catheter placement. RESULTS In each presentation (at ages 8 and 10 years for patient 1; age 15 years for patient 2), the patient experienced complete resolution of the priapism within 4-15 min of receiving N2 O (max 60%). The patients were discharged from the ED following each presentation and had no recurrence during the subsequent week. CONCLUSIONS Priapism is a challenging complication of SCD associated with long-term morbidity and a paucity of treatment options. Opioids are commonly used. Given the risks and inconsistent results of current recommended therapy, N2 O may represent a potential opioid-sparing treatment option for priapism presenting to the ED that warrants further investigation. Although anecdotal, N2 O inhalation is an intervention to consider during a time when a treating ED physician may have few alternatives.
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Affiliation(s)
- Michael H. Greenwald
- Department of Pediatrics Division of Emergency Medicine Emory University School of MedicineAtlanta GA
- Children's Healthcare of Atlanta Atlanta GA
| | - Colleen K. Gutman
- Department of Pediatrics Division of Emergency Medicine Emory University School of MedicineAtlanta GA
- Children's Healthcare of Atlanta Atlanta GA
| | - Claudia R. Morris
- Department of Pediatrics Division of Emergency Medicine Emory University School of MedicineAtlanta GA
- Children's Healthcare of Atlanta Atlanta GA
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13
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La Favor JD, Fu Z, Venkatraman V, Bivalacqua TJ, Van Eyk JE, Burnett AL. Molecular Profile of Priapism Associated with Low Nitric Oxide Bioavailability. J Proteome Res 2018; 17:1031-1040. [PMID: 29394072 DOI: 10.1021/acs.jproteome.7b00657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Priapism is a disorder in which prolonged penile erection persists uncontrollably, potentially leading to tissue damage. Priapism commonly afflicts patient populations with severely low nitric oxide (NO) bioavailability. Because NO is a primary mediator of erection, the molecular mechanisms involved in priapism pathophysiology associated with low NO bioavailability are not well-understood. The objective of this study was to identify dysregulated molecular targets and signaling pathways in penile tissue of a mouse model of low NO bioavailability that have potential relevance to priapism. Neuronal plus endothelial NO synthase double knockout mice (NOS1/3-/-) were used as a model of low NO bioavailability. Priapic-like activity was demonstrated in the NOS1/3-/- mice relative to wild-type (WT) mice by the measurement of prolonged erections following cessation of electrical stimulation of the cavernous nerve. Penile tissue was processed and analyzed by reverse-phase liquid chromatography tandem mass spectrometry. As a result, 1279 total proteins were identified and quantified by spectral counting, 46 of which were down-regulated and 110 of which were up-regulated in NOS1/3-/- versus WT (P < 0.05). Ingenuity Pathway Analysis of differentially expressed proteins revealed increased protein kinase A and G-protein coupled receptor signaling in NOS1/3-/- penises, which represent potential mechanisms contributing to priapism for secondary to low NO bioavailability.
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Affiliation(s)
| | | | - Vidya Venkatraman
- Advanced Clinical Biosystems Research Institute, Department of Medicine and The Heart Institute, Cedars-Sinai Medical Center , Los Angeles, California 90048, United States
| | | | - Jennifer E Van Eyk
- Advanced Clinical Biosystems Research Institute, Department of Medicine and The Heart Institute, Cedars-Sinai Medical Center , Los Angeles, California 90048, United States
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Musicki B, Karakus S, Akakpo W, Silva FH, Liu J, Chen H, Zirkin BR, Burnett AL. Testosterone replacement in transgenic sickle cell mice controls priapic activity and upregulates PDE5 expression and eNOS activity in the penis. Andrology 2017; 6:184-191. [PMID: 29145710 DOI: 10.1111/andr.12442] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/30/2017] [Accepted: 10/04/2017] [Indexed: 01/02/2023]
Abstract
Sickle cell disease (SCD)-associated priapism is characterized by decreased nitric oxide (NO) signaling and downregulated phosphodiesterase (PDE)5 protein expression and activity in the penis. Priapism is also associated with testosterone deficiency, but molecular mechanisms underlying testosterone effects in the penis in SCD are not known. Given the critical role of androgens in erection physiology and NO synthase (NOS)/PDE5 expression, we hypothesized that testosterone replacement to eugonadal testosterone levels reduces priapism by reversing impaired endothelial (e)NOS activity and molecular abnormalities involving PDE5. Adult male transgenic Berkeley sickle cell (Sickle) and wild-type (WT) mice were implanted with testosterone pellets, which release 1.2 μg testosterone/day for 21 days, or vehicle. After 21 days, animals underwent erectile function assessment followed by collection of blood for serum testosterone measurements, penes for molecular analysis, and seminal vesicles as testosterone-responsive tissue. Serum testosterone levels were measured by radioimmunoassay; protein expressions of PDE5, α-smooth muscle actin, eNOS and nNOS, and phosphorylation of PDE5 at Ser-92, eNOS at Ser-1177, neuronal (n) NOS at Ser-1412, and Akt at Ser-473 were measured by Western blot in penile tissue. Testosterone treatment reversed downregulated serum testosterone levels and increased (p < 0.05) the weight of seminal vesicles in Sickle mice to levels comparable to that of WT mice, indicating restored testosterone levels in Sickle mice. Testosterone treatment reduced (p < 0.05) prolonged detumescence in Sickle mice and normalized downregulated P-PDE5 (Ser-92), PDE5, P-eNOS (Ser-1177), and P-Akt (Ser-473) protein expressions in the Sickle mouse penis. Testosterone treatment did not affect P-nNOS (Ser-1412), eNOS, nNOS, or α-smooth muscle actin protein expressions in the Sickle mouse penis. In conclusion, in the mouse model of human SCD, increasing testosterone to eugonadal levels reduced priapic activity and reversed impaired Akt/eNOS activity and PDE5 protein expression in the penis.
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Affiliation(s)
- B Musicki
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - S Karakus
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - W Akakpo
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - F H Silva
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - J Liu
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - H Chen
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - B R Zirkin
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - A L Burnett
- The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins School of Medicine, Baltimore, MD, USA
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Abstract
Priapism, a persistent penile erection lasting longer than 4 hours and unrelated to sexual activity, is one of the most common emergencies treated by urologists. Priapism can be categorized as ischemic, recurrent ischemic (stuttering), and non-ischemic. Advances in understanding the pathophysiology of various types of priapism have led to targeted management strategies. This review aims to provide an up-to-date picture of the pathophysiology and management of priapism. A search of Medline and PubMed for relevant publications using the term "priapism" was performed. In addition to the "classical" articles, emphasis was placed on publications from January 2013 to September 2016 to evaluate the most recent literature available. Though advances in both basic and clinical research continue and effective treatment options are available, methods for the prevention of priapism continue to be elusive.
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Affiliation(s)
- Matthew Hudnall
- Department of Urology, University of California, San Francisco, San Francisco, CA 94143-0738, USA
| | - Amanda B Reed-Maldonado
- Department of Urology, University of California, San Francisco, San Francisco, CA 94143-0738, USA
| | - Tom F Lue
- Department of Urology, University of California, San Francisco, San Francisco, CA 94143-0738, USA
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Caspase-3 dependent nitrergic neuronal apoptosis following cavernous nerve injury is mediated via RhoA and ROCK activation in major pelvic ganglion. Sci Rep 2016; 6:29416. [PMID: 27388816 PMCID: PMC4937405 DOI: 10.1038/srep29416] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/06/2016] [Indexed: 01/28/2023] Open
Abstract
Axonal injury due to prostatectomy leads to Wallerian degeneration of the cavernous nerve (CN) and erectile dysfunction (ED). Return of potency is dependent on axonal regeneration and reinnervation of the penis. Following CN injury (CNI), RhoA and Rho-associated protein kinase (ROCK) increase in penile endothelial and smooth muscle cells. Previous studies indicate that nerve regeneration is hampered by activation of RhoA/ROCK pathway. We evaluated the role of RhoA/ROCK pathway in CN regulation following CNI using a validated rat model. CNI upregulated gene and protein expression of RhoA/ROCK and caspase-3 mediated apoptosis in the major pelvic ganglion (MPG). ROCK inhibitor (ROCK-I) prevented upregulation of RhoA/ROCK pathway as well as activation of caspase-3 in the MPG. Following CNI, there was decrease in the dimer to monomer ratio of neuronal nitric oxide synthase (nNOS) protein and lowered NOS activity in the MPG, which were prevented by ROCK-I. CNI lowered intracavernous pressure and impaired non-adrenergic non-cholinergic-mediated relaxation in the penis, consistent with ED. ROCK-I maintained the intracavernous pressure and non-adrenergic non-cholinergic-mediated relaxation in the penis following CNI. These results suggest that activation of RhoA/ROCK pathway mediates caspase-3 dependent apoptosis of nitrergic neurons in the MPG following CNI and that ROCK-I can prevent post-prostatectomy ED.
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