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Guillén-Gómez E, Pinilla-Macua I, Pérez-Torras S, Choi DS, Arce Y, Ballarín JA, Pastor-Anglada M, Díaz-Encarnación MM. New role of the human equilibrative nucleoside transporter 1 (hENT1) in epithelial-to-mesenchymal transition in renal tubular cells. J Cell Physiol 2012; 227:1521-8. [PMID: 21678404 DOI: 10.1002/jcp.22869] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Epithelial-to-mesenchymal transition (EMT) is an important pro-fibrotic event in which tubular epithelial cells are transformed into myofibroblasts. Nucleoside transporters (NT) are regulated by many factors and processes, some of which are involved in fibrosis, such as cytokines, inflammation, and proliferation. Equilibrative nucleoside transporter 1 (ENT1) has been proved to be the most widely expressed adenosine transporter. In that sense, ENT1 may be a key player in cell damage signaling. Here we analyze the role of human ENT1 (hENT1) in the EMT process in proximal tubular cells. Addition of the main inducer of EMT, the transforming growth factor-β1, to HK-2 cells increased hENT1 mRNA and protein level expression. ENT1-mediated adenosine uptake was also enhanced. When cells were incubated with dipyridamole to evaluate the potential contribution of ENT1 to EMT by blocking its transport activity, EMT was induced. Moreover, the knock down of hENT1 with siRNA induced EMT and collagen production in HK-2 cells. Kidneys isolated from ENT1 knockout mice showed higher levels of interstitial collagen and α-SMA positive cells than wild-type mice. Our results point to a new potential role of hENT1 as a modulator of EMT in proximal tubular cells. In this sense, hENT1 could be involved in renal protection processes, and the loss or reduced expression of hENT1 would lead to an increased vulnerability of cells to the onset and/or progression of renal fibrosis.
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Affiliation(s)
- Elena Guillén-Gómez
- Laboratori de Biologia Molecular, Universitat Autònoma de Barcelona, Fundació Puigvert, REDinREN, Institut Investigació Biosanitaria Sant Pau, Barcelona, Catalonia, Spain.
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Abstract
INTRODUCTION Priapism is a familiar problem to hematologists, well known for its association with sickle-cell disease (SCD). It also occurs in a variety of other hematological illnesses, nearly all forms of congenital hemolytic anemia, including other hemoglobinopathies and red blood cell membranopathies and enzymopathies. AIM Provide urologists with a comprehensive review of priapism in SCD, with an emphasis on the perspective of a practicing hematologist. METHODS Medline searches through July 2010 were conducted using the terms priapism, erectile dysfunction, and sickle cell. MAIN OUTCOME MEASURES Expert opinion was based on review of the medical literature related to this subject matter. RESULTS In men with SCD, large epidemiological studies have linked the risk of priapism to clinical markers of the severity of intravascular hemolysis. Extracellular hemoglobin and arginase released during hemolysis has been implicated in reducing nitric oxide bioavailability, although the relevance of hemolysis to vascular dysfunction has been challenged by some scientists. Consistent with the role of impairment of the nitric oxide axis, mice genetically deficient in nitric oxide production have also been shown to develop priapic activity. Provocative new data indicate that hemolysis-linked dysregulation of adenosine signaling in the penis contributes to priapism in sickle cell mice. Serious questions have arisen regarding the efficacy of mainstays of textbook dogma for treatment of acute severe priapism, including intravenous fluids, alkalinization, and exchange transfusion, and there is increasing acceptance for early aspiration and irrigation of the corpus cavernosum. CONCLUSION For patients with sickle cell with recurrent priapism, there is very limited evidence for a medical prophylaxis role for hydroxyurea, etilefrine, pseudoephedrine, leuprolide, sildenafil, and other agents. Recent publications have highlighted nitric oxide and adenosine signal transduction pathways as worthy of additional research. Research and clinical management of sickle-cell priapism is strengthened by multidisciplinary collaboration between hematologists and urologists.
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Affiliation(s)
- Gregory J Kato
- National Heart, Lung and Blood Institute, National Institutes of Health-Sickle Cell Vascular Disease Section, Cardiovascular and Pulmonary Branch, Bethesda, MD 20892-1476, USA.
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Bivalacqua TJ, Musicki B, Kutlu O, Burnett AL. New Insights into the Pathophysiology of Sickle Cell Disease‐Associated Priapism. J Sex Med 2012; 9:79-87. [DOI: 10.1111/j.1743-6109.2011.02288.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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54
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Drugs of the future for Peyronie's disease. Med Hypotheses 2011; 78:305-11. [PMID: 22154542 DOI: 10.1016/j.mehy.2011.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 11/08/2011] [Indexed: 01/01/2023]
Abstract
With the increasing awareness of Peyronie's disease (PD), the interest in new concept medications to treat the disorder is escalating. Profibrogenic factors such as transforming growth factor (TGF)-beta1, endothelin (ET-1), connective tissue growth factor (CTGF), angiotensin (Ang) II and platelet derived growth factor (PDGF), all appear to be involved in the pathogenesis of PD. β-Thymosins, pirfenidone, nitric oxide (NO) donors, phosphodiesterase (PDE)-5 inhibitors, matrix metalloproteinases (MMPs)/anti-tissue inhibitor of metalloproteinases (TIMP)-1 reduce collagen synthesis, while decorin, follistatin, and Smad 7 exert antifibrotic effects; all have been proposed for the treatment of PD. Alternative and/or novel approaches for the treatment of PD are needed in part because of the recognized multifactorial etiology of this complex disorder. A comprehensive approach for translating available experimental information into clinically effective drug trials for the treatment of PD is needed. We propose a multi-faceted approach for drug development to generate novel drug products for the treatment of PD.
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55
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Levey HR, Kutlu O, Bivalacqua TJ. Medical management of ischemic stuttering priapism: a contemporary review of the literature. Asian J Androl 2011; 14:156-63. [PMID: 22057380 DOI: 10.1038/aja.2011.114] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Priapism is defined as a prolonged and persistent erection of the penis without sexual stimulation. This is a poorly understood disease process with little information on the pathophysiology of this erectile disorder. Complications from this disorder are devastating due to the irreversible erectile damage and resultant erectile dysfunction (ED). Stuttering priapism, though relatively rare, affects a high prevalence of men with sickle-cell disease (SCD) and presents a challenging problem with guidelines for treatment lacking or resulting in permanent ED. The mechanisms involved in the development of priapism in this cohort are poorly characterized; therefore, medical management of priapism represents a therapeutic challenge to urologists. Additional research is warranted, so we can effectively target treatments for these patients with prevention as the goal. This review gives an introduction to stuttering priapism and its clinical significance, specifically with regards to the patient with SCD. Additionally, the proposed mechanisms behind its pathophysiology and a summary of the current and future targets for medical management are discussed.
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Affiliation(s)
- Helen R Levey
- The Arthur Smith Institute for Urology, North Shore - Long Island Jewish Health System, New Hyde Park, NY 11010, USA.
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56
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Andersson KE. Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction. Pharmacol Rev 2011; 63:811-59. [PMID: 21880989 DOI: 10.1124/pr.111.004515] [Citation(s) in RCA: 234] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.
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Affiliation(s)
- K-E Andersson
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, USA.
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57
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Tomlinson C, Rafii M, Ball RO, Pencharz P. Arginine synthesis from enteral glutamine in healthy adults in the fed state. Am J Physiol Endocrinol Metab 2011; 301:E267-73. [PMID: 21540446 DOI: 10.1152/ajpendo.00006.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies have documented transfer of labeled nitrogen from [2-(15)N]glutamine to citrulline and arginine in fasting human adults. Conversely, in neonates and piglets we have shown no synthesis of arginine from [2-(15)N]glutamate, and others have shown in mice that glutamine is a nitrogen, but not a carbon donor, for arginine synthesis. Therefore, we performed a multitracer study to determine whether glutamine is a nitrogen and/or carbon donor for arginine in healthy adult men. Two glutamine tracers, 2-(15)N and 1-(13)C, were given enterally to five healthy men fed a standardized milkshake diet. There was no difference in plasma enrichments between the two glutamine tracers. 1-(13)C isotopomers of citrulline and arginine were synthesized from [1-(13)C]glutamine. Three isotopomers each of citrulline and arginine were synthesized from the [2-(15)N]glutamine tracer: 2-(15)N, 5-(15)N, and 2,5-(15)N(2). Significantly greater enrichment was found of both [5-(15)N]arginine (0.75%) and citrulline (3.98%) compared with [2-(15)N]arginine (0.44%) and [2-(15)N]citrulline (2.62%), indicating the amino NH(2) from glutamine is mostly transferred to arginine and citrulline by transamination. Similarly, the enrichment of the 1-(13)C isotopomers was significantly less than the 2-(15)N isotopomers, suggesting rapid formation of α-ketoglutarate and recycling of the nitrogen label. Our results show that the carbon for 50% of newly synthesized arginine comes from dietary glutamine but that glutamine acts primarily as a nitrogen donor for arginine synthesis. Hence, studies using [2-(15)N]glutamine will overestimate arginine synthesis rates.
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Affiliation(s)
- Chris Tomlinson
- Division of Gastroenterology and Nutrition,Research Institute, The Hospital for Sick Children, University of Toronto, 555 University Ave., Toronto, Ontario, Canada
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58
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Grenz A, Dalton JH, Bauerle JD, Badulak A, Ridyard D, Gandjeva A, Aherne CM, Brodsky KS, Kim JH, Tuder RM, Eltzschig HK. Partial netrin-1 deficiency aggravates acute kidney injury. PLoS One 2011; 6:e14812. [PMID: 21625583 PMCID: PMC3098227 DOI: 10.1371/journal.pone.0014812] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 01/20/2011] [Indexed: 02/07/2023] Open
Abstract
The netrin family of secreted proteins provides migrational cues in the developing central nervous system. Recently, netrins have also been shown to regulate diverse processes beyond their functions in the brain, incluing the ochrestration of inflammatory events. Particularly netrin-1 has been implicated in dampening hypoxia-induced inflammation. Here, we hypothesized an anti-inflammatory role of endogenous netrin-1 in acute kidney injury (AKI). As homozygous deletion of netrin-1 is lethal, we studied mice with partial netrin-1 deletion (Ntn-1+/− mice) as a genetic model. In fact, Ntn-1+/− mice showed attenuated Ntn-1 levels at baseline and following ischemic AKI. Functional studies of AKI induced by 30 min of renal ischemia and reperfusion revealed enhanced kidney dysfunction in Ntn-1+/− mice as assessed by measurements of glomerular filtration, urine flow rate, urine electrolytes, serum creatinine and creatinine clearance. Consistent with these findings, histological studies indicated a more severe degree kidney injury. Similarly, elevations of renal and systemic inflammatory markers were enhanced in mice with partial netrin-1 deficiency. Finally, treatment of Ntn-1+/− mice with exogenous netrin-1 restored a normal phenotype during AKI. Taking together, these studies implicate endogenous netrin-1 in attenuating renal inflammation during AKI.
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Affiliation(s)
- Almut Grenz
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail: (AG); (HKE)
| | - Julee H. Dalton
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jessica D. Bauerle
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Alexander Badulak
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Douglas Ridyard
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Aneta Gandjeva
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Carol M. Aherne
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Kelley S. Brodsky
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jae-Hwan Kim
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Anesthesiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Rubin M. Tuder
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Holger K. Eltzschig
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail: (AG); (HKE)
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Dai Y, Zhang W, Wen J, Zhang Y, Kellems RE, Xia Y. A2B adenosine receptor-mediated induction of IL-6 promotes CKD. J Am Soc Nephrol 2011; 22:890-901. [PMID: 21511827 DOI: 10.1681/asn.2010080890] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Chronic elevation of adenosine, which occurs in the setting of repeated or prolonged tissue injury, can exacerbate cellular dysfunction, suggesting that it may contribute to the pathogenesis of CKD. Here, mice with chronically elevated levels of adenosine, resulting from a deficiency in adenosine deaminase (ADA), developed renal dysfunction and fibrosis. Both the administration of polyethylene glycol-modified ADA to reduce adenosine levels and the inhibition of the A(2B) adenosine receptor (A(2B)R) attenuated renal fibrosis and dysfunction. Furthermore, activation of A(2B)R promoted renal fibrosis in both mice infused with angiotensin II (Ang II) and mice subjected to unilateral ureteral obstruction (UUO). These three mouse models shared a similar profile of profibrotic gene expression in kidney tissue, suggesting that they share similar signaling pathways that lead to renal fibrosis. Finally, both genetic and pharmacologic approaches showed that the inflammatory cytokine IL-6 mediates adenosine-induced renal fibrosis downstream of A(2B)R. Taken together, these data suggest that A(2B)R-mediated induction of IL-6 contributes to renal fibrogenesis and shows potential therapeutic targets for CKD.
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Affiliation(s)
- Yingbo Dai
- Department of Biochemistry and Molecular Biology, University of Texas-Houston Medical School, Houston, Texas, USA
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Field JJ, Nathan DG, Linden J. Targeting iNKT cells for the treatment of sickle cell disease. Clin Immunol 2011; 140:177-83. [PMID: 21429807 DOI: 10.1016/j.clim.2011.03.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/23/2011] [Accepted: 03/02/2011] [Indexed: 12/19/2022]
Abstract
Sickle cell disease (SCD) causes widely disseminated vaso-occlusive episodes. Building on evidence implicating invariant NKT (iNKT) cells in the pathogenesis of ischemia/reperfusion injury, recent studies demonstrate that blockade of iNKT cell activation in mice with SCD reduces pulmonary inflammation and injury. In patients with SCD, iNKT cells in blood are increased in absolute number and activated in comparison to healthy controls. iNKT cell activation is reduced by agonists of adenosine 2A receptors (A(2A)Rs) such as the clinically approved coronary vasodilator, regadenoson. An ongoing multi-center, dose-finding and safety trial of infused regadenoson, has been initiated and is providing preliminary data about its safety and efficacy to treat SCD. Very high accumulation of adenosine may have deleterious effects in SCD through activation of adenosine 2B receptors that are insensitive to regadenoson. Future possible therapeutic approaches for treating SCD include selective A(2B)R antagonists and antibodies that deplete iNKT cells.
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Affiliation(s)
- Joshua J Field
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
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Feoktistov I, Biaggioni I. Role of adenosine A(2B) receptors in inflammation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:115-44. [PMID: 21586358 PMCID: PMC3748596 DOI: 10.1016/b978-0-12-385526-8.00005-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent progress in our understanding of the unique role of A(2B) receptors in the regulation of inflammation, immunity, and tissue repair was considerably facilitated with the introduction of new pharmacological and genetic tools. However, it also led to seemingly conflicting conclusions on the role of A(2B) adenosine receptors in inflammation with some publications indicating proinflammatory effects and others suggesting the opposite. This chapter reviews the functions of A(2B) receptors in various cell types related to inflammation and integrated effects of A(2B) receptor modulation in several animal models of inflammation. It is argued that translation of current findings into novel therapies would require a better understanding of A(2B) receptor functions in diverse types of inflammatory responses in various tissues and at different points of their progression.
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Affiliation(s)
- Igor Feoktistov
- Department of Medicine, Vanderbilt University, Division of Cardiovascular Medicine, Nashville, Tennessee, USA
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Musicki B, Champion HC, Hsu LL, Bivalacqua TJ, Burnett AL. Post-translational inactivation of endothelial nitric oxide synthase in the transgenic sickle cell mouse penis. J Sex Med 2010; 8:419-26. [PMID: 21143412 DOI: 10.1111/j.1743-6109.2010.02123.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Sickle cell disease (SCD)-associated priapism is characterized by endothelial nitric oxide synthase (eNOS) dysfunction in the penis. However, the mechanism of decreased eNOS function/activation in the penis in association with SCD is not known. AIMS Our hypothesis in the present study was that eNOS is functionally inactivated in the SCD penis in association with impairments in eNOS post-translational phosphorylation and the enzyme's interactions with its regulatory proteins. METHODS Sickle cell transgenic (sickle) mice were used as an animal model of SCD. Wild-type (WT) mice served as controls. Penes were excised at baseline for molecular studies. eNOS phosphorylation on Ser-1177 (positive regulatory site) and Thr-495 (negative regulatory site), total eNOS, and phosphorylated AKT (upstream mediator of eNOS phosphorylation on Ser-1177) expressions, and eNOS interactions with heat-shock protein 90 (HSP90) and caveolin-1 were measured by Western blot. Constitutive NOS catalytic activity was measured by conversion of L-[14C]arginine-to-L-[14C]citrulline in the presence of calcium. MAIN OUTCOME MEASURES Molecular mechanisms of eNOS dysfunction in the sickle mouse penis. RESULTS eNOS phosphorylated on Ser-1177, an active portion of eNOS, was decreased in the sickle mouse penis compared with WT penis. eNOS interaction with its positive protein regulator HSP90, but not with its negative protein regulator caveolin-1, and phosphorylated AKT expression, as well as constitutive NOS activity, were also decreased in the sickle mouse penis compared with WT penis. eNOS phosphorylated on Thr-495, total eNOS, HSP90, and caveolin-1 protein expressions in the penis were not affected by SCD. CONCLUSIONS These findings provide a molecular basis for chronically reduced eNOS function in the penis by SCD, which involves decreased eNOS phosphorylation on Ser-1177 and decreased eNOS-HSP90 interaction.
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Affiliation(s)
- Biljana Musicki
- The Johns Hopkins University, Department of Urology, Baltimore, MD 21287, USA.
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Priapism in sickle cell anemia: emerging mechanistic understanding and better preventative strategies. Anemia 2010; 2011:297364. [PMID: 21490762 PMCID: PMC3066554 DOI: 10.1155/2011/297364] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 10/11/2010] [Accepted: 10/29/2010] [Indexed: 11/17/2022] Open
Abstract
Sickle cell anemia is a common and disabling disorder profoundly affecting mortality as well as quality of life. Up to 35% of men with sickle cell disease are affected by painful, prolonged erections termed ischemic priapism. A priapic episode may result in fibrosis and permanent erectile dysfunction. The severity of sickle cell disease manifestations is variable dependent on a number of contributing genetic factors; however, priapism tends to cluster with other severe vascular complications including pulmonary hypertension, leg ulceration, and overall risk of death. The mechanisms underlying priapism in sickle cell disease have begun to be elucidated including hemolysis-mediated dysregulation of the nitric oxide signaling pathway and dysregulation of adenosine-mediated vasodilation. A better understanding of these mechanisms is leading toward novel preventative strategies. This paper will focus on the mechanisms underlying development of ischemic priapism in sickle cell disease, current acute and preventative treatment strategies, and future directions for improved management of this disorder.
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Abstract
INTRODUCTION Priapism is an enigmatic yet devastating clinical phenomenon. In the last two decades, the use of various animal models to study this disorder has dramatically advanced our understanding of this mysterious disorder. AIM This report reviews various animal models used to study ischemic priapism and informs basic science researchers the broad view of priapism research. METHODS Retrospective review of pertinent literature from the last two decades via PubMed search using the keywords "ischemic priapism" and "priapism model." MAIN OUTCOME MEASURES Findings on the animal models used in ischemic priapism research and its advantages and limitations. RESULTS In vitro and in vivo animal models varying from dogs, cats, rabbits, rats to mice were used in priapism research. In vitro models included: (i) corpora cavernosa smooth muscle (CCSM) strip in organ bath; (ii) corporal tissue binding assay; (iii) CCSM cell culture under hypoxia/anoxia. In vivo models could be categorized as: (i) pharmacologically induced by corpus cavernosum medicine injection; (ii) ventilation induced by tidal volume control; (iii) mechanical induced by a constrictor band placed around the base of the penis combined with induced erection; (iv) genetic engineered by intracorporal gene transfer, transgenic, or gene knock-out. CONCLUSIONS The ischemic priapism animal models are shifting from pharmaceutically or mechanically induced to genetically engineered. The knowledge generated by those models is enhancing our understanding and management of this clinical challenge.
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Affiliation(s)
- Qiang Dong
- Department of Urology, West China Hospital, Sichuan University, Chengdu, China
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