Therapy insight: Priapism associated with hematologic dyscrasias

Novel erectile analyses revealed augmentable penile Lyve-1, the lymphatic marker, expression

Purpose

The pathophysiology of penis extends to erectile dysfunction (ED) to conditions including sexually transmitted diseases (STDs) and cancer. To date, there has been little research evaluating vascular drainage from the penis. We aimed to evaluate penile blood flow in vivo and analyze its possible relationship with the lymphatic maker.

Materials and Methods

We established an in vivo system designed to assess the dynamic blood outflow from the corpus cavernosum (CC) by dye injection. To analyze lymphatic characteristics in the CC, the expression of Lyve-1, the key lymphatic endothelium marker, was examined by the in vitro system and lipopolysaccharide (LPS) injection to mimic the inflammatory conditions.

Results

A novel cavernography methods enable high-resolution morphological and functional blood drainage analysis. The expression of Lyve-1 was detected along the sinusoids. Furthermore, its prominent expression was also observed after penile LPS injection and in the erectile condition.

Conclusions

The current in vivo system will potentially contribute to the assessment of penile pathology from a novel viewpoint. In addition, current analyses revealed inducible Lyve-1 expression for LPS injection and the erection state, which requires further analyses on penile lymphatic system.

Priapism at Diagnosis of Pediatric Chronic Myeloid Leukemia: Data Derived from a Large Cohort of Children and Teenagers and a Narrative Review on Priapism Management

Pediatric chronic myeloid leukemia (CML) is a very rare malignancy (age-related incidence 0.1/100,000) typically presenting with leucocyte counts >100,000/µL. However, clinical signs of leukostasis are observed at diagnosis in only approximately 10% of all cases and among these, priapism is infrequent. Here, we analyze data from pediatric CML registries on the occurrence of priapism heralding diagnosis of CML in 16/491 (3.2%) boys (median age 13.5 years, range 4-18) with pediatric CML. In the cohort investigated, duration of priapism resulting in a diagnosis of CML was not reported in 5 patients, and in the remaining 11 patients, occurred as stuttering priapism over 3 months (n = 1), over 6 weeks (n = 1), over 1-2 weeks (n = 2), over several days (n = 2), or 24 h (n = 1), while the remaining 4 boys reported continuous erection lasting over 11-12 h. All patients exhibited splenomegaly and massive leukocytosis (median WBC 470,000/µL, range 236,700-899,000). Interventions to treat priapism were unknown in 5 patients, and in the remaining cohort, comprised intravenous fluids ± heparin (n = 2), penile puncture (n = 5) ± injection of sympathomimetics (n = 4) ± intracavernous shunt operation (n = 1) paralleled by leukocyte-reductive measures. Management without penile puncture by leukapheresis or exchange transfusion was performed in 3 boys. In total, 7 out 15 (47%) long-term survivors (median age 20 years, range 19-25) responded to a questionnaire. All had maintained full erectile function; however, 5/7 had presented with stuttering priapism while in the remaining 2 patients priapism had lasted <12 h until intervention. At its extreme, low-flow priapism lasting for longer than 24 h may result in partial or total impotence by erectile dysfunction. This physical disability can exert a large psychological impact on patients' lives. In a narrative review fashion, we analyzed the literature on priapism in boys with CML which is by categorization stuttering or persisting as mostly painful, ischemic (low-flow) priapism. Details on the pathophysiology are discussed on the background of the different blood rheology of hyperleukocytosis in acute and chronic leukemias. In addition to the data collected, instructive case vignettes demonstrate the diagnostic and treatment approaches and the outcome of boys presenting with priapism. An algorithm for management of priapism in a stepwise fashion is presented. All approaches must be performed in parallel with cytoreductive treatment of leukostasis in CML which comprises leukapheresis and exchange transfusions ± cytotoxic chemotherapy.

Establishment of mouse line showing inducible priapism-like phenotypes

Purpose

Penile research is expected to reveal new targets for treatment and prevention of the complex mechanisms of its disorder including erectile dysfunction (ED). Thus, analyses of the molecular processes of penile ED and continuous erection as priapism are essential issues of reproductive medicine.

Methods

By performing mouse N‐ethyl‐N‐nitrosourea mutagenesis and exome sequencing, we established a novel mouse line displaying protruded genitalia phenotype (PGP; priapism‐like phenotype) and identified a novel Pitpna gene mutation for PGP. Extensive histological analyses on the Pitpna mutant and intracavernous pressure measurement (ICP) and liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI/MS)/MS analyses were performed.

Results

We evaluated the role of phospholipids during erection for the first time and showed the mutants of inducible phenotypes of priapism. Moreover, quantitative analysis using LC–ESI/MS/MS revealed that the level of phosphatidylinositol (PI) was significantly lower in the mutant penile samples. These results imply that PI may contribute to penile erection by PITPα.

Conclusions

Our findings suggest that the current mutant is a mouse model for priapism and abnormalities in PI signaling pathways through PITPα may lead to priapism providing an attractive novel therapeutic target in its treatment.

Comparison of outcomes in malignant vs. non-malignant ischemic priapism: 12-year experience from a tertiary center

OBJECTIVE

Data on outcome of patients with ischemic priapism (IP) due to malignant causes are scant. In this study, we compared outcome of patients with malignant vs. non-malignant IP in adult North Indian men.

MATERIAL AND METHODS

We analyzed medical records of patients with IP who presented to a large tertiary care referral center from August 2005 to July 2017.

RESULTS

Data of 71 patients were analyzed. The median age was 30 years (range 17-65). The average duration of symptoms was 4.39 days (range 1-10). Most common etiology was idiopathic in 29 (40.84%), chronic myeloid leukemia (CML) in 24 (33.80%), and drug-induced in 15 patients. Thirty-eight patients underwent distal shunts, while nine patients underwent proximal shunt procedure. Men with malignant priapism (CML) had significantly lower success rates with interventions, prolonged hospital stay, and higher complications (p<0.05). Most complications after shunt surgery were minor (Clavein grade 1 and 2). After shunt surgery, bleeding at shunt site was observed in 14 cases, and wound infection developed in five patients. Prevalence of erectile dysfunction in patients at follow-up was high.

CONCLUSION

Men with malignant priapism (CML) had significantly lower success rates with interventions, prolonged hospital stay, and higher complications than men with non-malignant priapism.

Risk Factors for Priapism Readmission

INTRODUCTION

Priapism is a urologic emergency with a tendency to recur in some patients. The frequency of, time to, and risk factors for priapism recurrence have not been well characterized.

AIM

To identify predictors of priapism readmission.

METHODS

We used the New York Statewide Planning and Research Cooperative System database to identify patients presenting to emergency departments with priapism from 2005 through 2014. Patients were tracked up to 12 months after initial presentation. Proportional hazards regression was used to identify risk factors for priapism readmission.

MAIN OUTCOME MEASURES

Readmissions for priapism.

RESULTS

The analytic cohort included 3,372 men with a diagnosis of priapism. The average age at first presentation was 39 ± 18 years and 40% were black. Within 1 year, 24% of patients were readmitted for recurrent priapism, 68% of whom were readmitted within 60 days. On multivariate analysis, sickle cell disease (hazard ratio [HR] = 2.5, 95% CI = 2.0-3.0), drug abuse or psychiatric disease (HR = 1.9, 95% CI = 1.6-2.2), erectile dysfunction history (HR = 1.9, 95% CI = 1.5-2.3), other than commercial medical insurance (HR = 1.2, 95% CI = 1.0-1.4), and inpatient admission for initial priapism event (HR = 0.5, 95% CI = 0.4-0.6) were significant risk factors for readmission.

CONCLUSION

Nearly one fourth of patients with priapism were readmitted for recurrent priapism within 1 year of initial presentation. Most readmissions were within 60 days. Future research should focus on strategies to decrease recurrences in high-risk patients.

Management of priapism in adult men

This study aims to present the management of priapism in adult men in Port Harcourt, Nigeria. All patients who presented with priapism in 2 hospitals in Port Harcourt from July 2007 to April 2014 were prospectively studied. Treatment was assigned based on clinical presentation. Data analyzed included: age on clinical presentation, risk factor, mode, and outcome of management. There were 18 patients aged 17 to 60 years (median age: 30 years). Three patients (16.7%) presented with stuttering priapism. Most of the patients presented after 24 hours of onset. Sixteen patients (89.9%) had hematological disorders. Five patients (27.8%) took suspected aphrodisiac medications. Seven patients (38.9%) were managed conservatively. The rest achieved detumescence following glandulo-cavernous shunting. Erectile function after treatment was satisfactory in 5 patients (27.8%). The commonest cause of priapism in Port Harcourt was hematological disorder. Most of the patients presented late. Prevalence of erectile dysfunction after treatment was high.

New insights into sickle cell disease: a disease of hypoxia

PURPOSE OF REVIEW

Sickle cell disease (SCD) is a devastating genetic disorder caused by a single amino acid substitution in β-globin. Although the condition was first described more than a 100 years ago, treatment options remain scarce and unsatisfactory. This review summarizes recent findings that may provide novel insight into therapeutic approaches to SCD treatment.

RECENT FINDINGS

Because of insufficient numbers of erythrocytes for oxygen delivery, SCD patients constantly face hypoxia. Adenosine is well known as a key signaling nucleoside that orchestrates a multifaceted physiological response to hypoxia. Recent studies have revealed that adenosine concentrations are significantly elevated in SCD and contribute to disease pathology by activating adenosine receptors on red blood cells. Apart from adenosine, hypoxia also causes hemoglobin release via hemolysis. Studies on free hemoglobin in circulation have uncovered another two important molecules: nitric oxide and heme oxygenase-1.

SUMMARY

The core of SCD pathology is erythrocyte sickling under hypoxic conditions, leading to vaso-occlusion and hemolysis. Deeper and more comprehensive understanding of SCD as a disease of hypoxia will provide us new therapeutic targets for SCD treatment.

Priapism is associated with sleep hypoxemia in sickle cell disease

PURPOSE

We assessed penile rigidity during sleep and the relationship of sleep abnormalities with priapism in adults with sickle cell disease.

MATERIALS AND METHODS

This was a case-control study of 18 patients with sickle cell disease and a history of priapism during the previous year, and 16 controls with sickle cell disease. Participants underwent overnight polysomnography and RigiScan® Plus recording to detect penile rigidity oscillations.

RESULTS

The priapism group (cases) showed a higher apnea-hypopnea index and oxyhemoglobin desaturation parameters than controls. A lower positive correlation between the apnea-hypopnea index and oxyhemoglobin desaturation time was observed in cases than in controls (Spearman coefficient ρ = 0.49, p = 0.05 vs ρ = 0.76, p <0.01), suggesting that desaturation events occurred independently of apnea. Two controls and 14 cases had a total sleep time that was greater than 10% with oxyhemoglobin saturation less than 90% but without CO(2) retention. Penile rigidity events were observed during rapid eye movement sleep and during stage 2 of nonrapid eye movement sleep, particularly in cases. The duration of penile rigidity events concomitant to respiratory events was higher in cases than in controls. Regression analysis revealed that the periodic limb movement and desaturation indexes were associated with priapism after adjusting for rapid eye movement sleep and lung involvement. Finally, oxyhemoglobin saturation less than 90% was associated with priapism after adjusting for lung involvement, hyperhemolysis and the apnea-hypopnea index.

CONCLUSIONS

Oxyhemoglobin desaturation during sleep was associated with priapism history. It may underlie the distribution pattern of penile rigidity events during sleep in these patients.

Adenosine signaling in normal and sickle erythrocytes and beyond

Sickle cell disease (SCD) is a debilitating hemolytic genetic disorder with high morbidity and mortality affecting millions of individuals worldwide. Although SCD was discovered more than a century ago, no effective mechanism-based prevention and treatment are available due to poorly understood molecular basis of sickling, the fundamental pathogenic process of the disease. SCD patients constantly face hypoxia. One of the best-known signaling molecules to be induced under hypoxic conditions is adenosine. Recent studies demonstrate that hypoxia-mediated elevated adenosine signaling plays an important role in normal erythrocyte physiology. In contrast, elevated adenosine signaling contributes to sickling and multiple life threatening complications including tissue damage, pulmonary dysfunction and priapism. Here, we summarize recent research on the role of adenosine signaling in normal and sickle erythrocytes, progression of the disease and therapeutic implications. In normal erythrocytes, both genetic and pharmacological studies demonstrate that adenosine can enhance 2,3-bisphosphoglycerate (2,3-BPG) production via A(2B) receptor (ADORA2B) activation, suggesting that elevated adenosine has an unrecognized role in normal erythrocytes to promote O(2) release and prevent acute ischemic tissue injury. However, in sickle erythrocytes, the beneficial role of excessive adenosine-mediated 2,3-BPG induction becomes detrimental by promoting deoxygenation, polymerization of sickle hemoglobin and subsequent sickling. Additionally, adenosine signaling via the A(2A) receptor (ADORA2A) on invariant natural killer T (iNKT) cells inhibits iNKT cell activation and attenuates pulmonary dysfunction in SCD mice. Finally, elevated adenosine coupled with ADORA2BR activation is responsible for priapism, a dangerous complication seen in SCD. Overall, the research reviewed here reveals a differential role of elevated adenosine in normal erythrocytes, sickle erythrocytes, iNK cells and progression of disease. Thus, adenosine signaling represents a potentially important therapeutic target for the treatment and prevention of disease.

Pediatric genitourinary emergencies

Pediatric medical complaints and differential diagnoses often vary from adults, requiring a specialized knowledge base and behavioral skill set. This article addresses a variety of congenital and acquired pediatric genitourinary disorders. Genitourinary emergencies include paraphismosis, priapism, serious infection, significant traumatic injury and gonadal torsion.

Adenosine deaminase enzyme therapy prevents and reverses the heightened cavernosal relaxation in priapism

INTRODUCTION

Priapism featured with painful prolonged penile erection is dangerous and commonly seen in sickle cell disease (SCD). The preventive approaches or effective treatment options for the disorder are limited because of poor understanding of its pathogenesis. Recent studies have revealed a novel role of excess adenosine in priapism caused by heightened cavernosal relaxation, and therefore present an intriguing mechanism-based therapeutic possibility.

AIM

The aim of this study was to determine the therapeutic effects of adenosine deaminase (ADA) enzyme therapy to lower adenosine in priapism.

METHODS

Both ADA-deficient mice and SCD transgenic (Tg) mice display priapism caused by excessive adenosine. Thus, we used these two distinct lines of mouse models of priapism as our investigative tools. Specifically, we treated both of these mice with different dosages of polyethylene glycol-modified ADA (PEG-ADA) to reduce adenosine levels in vivo. At the end points of the experiments, we evaluated the therapeutic effects of PEG-ADA treatment by measuring adenosine levels and monitoring the cavernosal relaxation.

MAIN OUTCOME MEASURES

Adenosine levels in penile tissues were measured by high-performance liquid chromatography, and cavernosal relaxation was quantified by electrical field stimulation (EFS)-induced corporal cavernosal strip (CCS) assays.

RESULTS

We found that lowering adenosine levels in penile tissues by PEG-ADA treatment from birth in ADA-deficient mice prevented the increased EFS-induced CCS relaxation associated with priapism. Intriguingly, in both ADA-deficient mice and SCD Tg mice with established priapism, we found that normalization of adenosine levels in penile tissues by PEG-ADA treatment relieved the heightened EFS-induced cavernosal relaxation in priapism.

CONCLUSIONS

Our studies have identified that PEG-ADA is a novel, safe, and mechanism-based drug to prevent and correct excess adenosine-mediated increased cavernosal relaxation seen in two independent priapic animal models, and suggested its therapeutic possibility in men suffering from priapism.

Increased cavernosal relaxations in sickle cell mice priapism are associated with alterations in the NO-cGMP signaling pathway

INTRODUCTION

Priapism is defined as prolonged and persistent penile erection, unassociated with sexual interest or stimulation, and is one of the many serious complications associated with sickle cell disease (SCD).

AIM

The aim of this study was to evaluate the role of the NO-cGMP signaling pathway in priapism in Berkeley murine model of SCD (SS).

METHODS

SS mice and C57BL/6 mice (control) penile tissues were removed and the erectile tissue within the corpus cavernosum (CC) was surgically dissected free. The strips were mounted in 10 mL organ baths containing Krebs solution at 37 degrees C (95% O(2), 5% CO(2), pH 7.4), and vertically suspended between two metal hooks.

MAIN OUTCOME MEASURES

Cumulative concentration-response curves were constructed for acetylcholine (ACh; endothelium-dependent responses), sodium nitroprusside (SNP; endothelium-independent relaxations) and BAY 41-2272 (a potent activator of NO-independent site of soluble guanylate cyclase) in CC precontracted with phenylephrine. Cavernosal responses induced by frequency-dependent electrical field stimulation (EFS) were also carried out to evaluate the nitrergic cavernosal relaxations.

RESULTS

In SS mice, ACh-induced cavernosal relaxations were leftward shifted by 2.6-fold (P < 0.01) that was accompanied by increases in the maximal responses (78 +/- 5% and 60 +/- 3% in SS and C57B6/6J mice, respectively). Similarly, SNP- and BAY 41-2272-induced CC relaxations were leftward shifted by approximately 3.3- and 2.2-fold (P < 0.01) in SS mice, respectively. A significant increase in maximal responses to SNP and BAY 41-2272 in SS mice was also observed (113 +/- 6% and 124 +/- 5%, respectively) compared with C57B6/6J mice (83 +/- 4% and 99 +/- 2%, respectively). The EFS-induced cavernosal relaxations were also significantly higher SS mice.

CONCLUSION

These results showed that SS mice exhibit amplified corpus carvenosum relaxation response mediated by NO-cGMP signaling pathway. Intervention in this signaling pathway may be a potential therapeutic target to treat SCD priapism.

Excess adenosine in murine penile erectile tissues contributes to priapism via A2B adenosine receptor signaling

Priapism, abnormally prolonged penile erection in the absence of sexual excitation, is associated with ischemia-mediated erectile tissue damage and subsequent erectile dysfunction. It is common among males with sickle cell disease (SCD), and SCD transgenic mice are an accepted model of the disorder. Current strategies to manage priapism suffer from a poor fundamental understanding of the molecular mechanisms underlying the disorder. Here we report that mice lacking adenosine deaminase (ADA), an enzyme necessary for the breakdown of adenosine, displayed unexpected priapic activity. ADA enzyme therapy successfully corrected the priapic activity both in vivo and in vitro, suggesting that it was dependent on elevated adenosine levels. Further genetic and pharmacologic evidence demonstrated that A2B adenosine receptor-mediated (A2BR-mediated) cAMP and cGMP induction was required for elevated adenosine-induced prolonged penile erection. Finally, priapic activity in SCD transgenic mice was also caused by elevated adenosine levels and A2BR activation. Thus, we have shown that excessive adenosine accumulation in the penis contributes to priapism through increased A2BR signaling in both Ada -/- and SCD transgenic mice. These findings provide insight regarding the molecular basis of priapism and suggest that strategies to either reduce adenosine or block A2BR activation may prove beneficial in the treatment of this disorder.

Priapism in the Oncology Setting

CASE STUDY

N.L. is a 20-year-old Caucasian man with no significant medical history. He presented to the hospital with a two-day history of feeling ill with intermittent nausea, vomiting, blurred vision, and headache. He also noted slurred speech and left-upper-quadrant fullness for almost a month.