Discover the most talked about and latest scientific content & concepts.

Concept: Priapism


Background The up-regulation of P-selectin in endothelial cells and platelets contributes to the cell-cell interactions that are involved in the pathogenesis of vaso-occlusion and sickle cell-related pain crises. The safety and efficacy of crizanlizumab, an antibody against the adhesion molecule P-selectin, were evaluated in patients with sickle cell disease. Methods In this double-blind, randomized, placebo-controlled, phase 2 trial, we assigned patients to receive low-dose crizanlizumab (2.5 mg per kilogram of body weight), high-dose crizanlizumab (5.0 mg per kilogram), or placebo, administered intravenously 14 times over a period of 52 weeks. Patients who were receiving concomitant hydroxyurea as well as those not receiving hydroxyurea were included in the study. The primary end point was the annual rate of sickle cell-related pain crises with high-dose crizanlizumab versus placebo. The annual rate of days hospitalized, the times to first and second crises, annual rates of uncomplicated crises (defined as crises other than the acute chest syndrome, hepatic sequestration, splenic sequestration, or priapism) and the acute chest syndrome, and patient-reported outcomes were also assessed. Results A total of 198 patients underwent randomization at 60 sites. The median rate of crises per year was 1.63 with high-dose crizanlizumab versus 2.98 with placebo (indicating a 45.3% lower rate with high-dose crizanlizumab, P=0.01). The median time to the first crisis was significantly longer with high-dose crizanlizumab than with placebo (4.07 vs. 1.38 months, P=0.001), as was the median time to the second crisis (10.32 vs. 5.09 months, P=0.02). The median rate of uncomplicated crises per year was 1.08 with high-dose crizanlizumab, as compared with 2.91 with placebo (indicating a 62.9% lower rate with high-dose crizanlizumab, P=0.02). Adverse events that occurred in 10% or more of the patients in either active-treatment group and at a frequency that was at least twice as high as that in the placebo group were arthralgia, diarrhea, pruritus, vomiting, and chest pain. Conclusions In patients with sickle cell disease, crizanlizumab therapy resulted in a significantly lower rate of sickle cell-related pain crises than placebo and was associated with a low incidence of adverse events. (Funded by Selexys Pharmaceuticals and others; SUSTAIN number, NCT01895361 .).

Concepts: Time, Clinical trial, Medical terms, Red blood cell, Placebo, Sickle-cell disease, Sickle, Priapism


Aneurysmal dilatation of the corpora cavernosa can occur because of recurrent priapism in the setting of sickle cell disease.

Concepts: Andrology, Erectile dysfunction, Sickle-cell disease, Sickle, Erection, Corpus cavernosum penis, Priapism


We evaluated the therapeutic potential of a sustained nitric oxide (NO)-releasing compound to correct the molecular hallmarks and pathophysiology of priapism, an important but poorly characterized erectile disorder. 1,5-Bis-(dihexyl-N-nitrosoamino)-2,4-dinitrobenzene (C6') and an inactive form of the compound [1,5-bis-(dihexylamino)-2,4-dinitrobenzene (C6)] were tested in neuronal cell cultures and penile lysates for NO release (Griess assay) and biological activity (cGMP production). The effect of local depot C6' or C6 was evaluated in mice with a priapic phenotype due to double neuronal and endothelial NO synthase deletion (dNOS(-/-)) or human sickle hemoglobin transgenic expression (Sickle). Changes in NO signaling molecules and reactive oxygen species (ROS) surrogates were assessed by Western blot. The physiological response after C6' treatment was assessed using an established model of electrically stimulated penile erection. C6' generated NO, increased cGMP, and dose dependently increased NO metabolites. C6' treatment reversed abnormalities in key penile erection signaling molecules, including phosphodiesterase type 5, phosphorylated endothelial nitric oxide synthase, and phosphorylated vasodilator-stimulated phosphoprotein. In Sickle mice, C6' also attenuated the increased ROS markers gp91(phox), 4-hydroxynonenal, and 3-nitrotyrosine. Finally, C6' corrected the excessive priapic erection response of dNOS(-/-) mice. Exogenous sustained NO release from C6' corrects pathological erectile signaling in mouse models of priapism and suggests novel approaches to human therapy.-Lagoda, G., Sezen, S. F., Hurt, K. J., Cabrini, M. R., Mohanty, D. K., Burnett, A. L. Sustained nitric oxide (NO)-releasing compound reverses dysregulated NO signal transduction in priapism.

Concepts: Oxygen, Molecular biology, Nitric oxide, Erectile dysfunction, Nitric oxide synthase, Penis, Erection, Priapism


Current non-surgical strategies employed to treat erectile dysfunction (ED) target the vascular component of erection physiology. The Viberect handheld device (Reflexonic, LLC, Chambersburg, PA, USA) is a new FDA-cleared ED treatment, which exploits vibratory stimulation of genital afferent nerves for provoking erections. The aim of this study was to evaluate the clinical feasibility of the Viberect device for the achievement of penile erection and rigidity.

Concepts: Sexual intercourse, Erectile dysfunction, Penis, Erection, Sexual arousal, Priapism



To explore the therapeutic potential of PnTx2-6 injected 3 times a week for 4 weeks into the intracavernosal tissue in a rat model of bilateral cavernous nerve crush injury (BCNI).

Concepts: Protein, Blood, Erectile dysfunction, Toxin, Spider, Priapism, Brazilian wandering spider, Tx2-6


We presented a case of a postoperative patient with low-flow priapism, possibly initiated by propofol-based anaesthesia or epidural anaesthesia. The delay in diagnosing priapism resulted in emergency interventions with a partially successful effect and eventually permanent erectile dysfunction. Due to the delay in treatment, erectile dysfunction ensued and was manageable with medication; hence, the patient decided against a penile prosthesis.

Concepts: Erectile dysfunction, Caesarean section, Penis, Peyronie's disease, Local anesthetic, Erection, Sexual health, Priapism


Evidence from animal models replicating postradical prostatectomy erectile dysfunction (pRP-ED) suggests intracavernous injection of bone marrow-mononuclear cells (BM-MNCs) as a promising treatment approach for pRP-ED. We conducted a phase ½ pilot clinical trial of intracavernous autologous BM-MNC injection to treat pRP-ED (NCT01089387). Twelve patients with localized prostate cancer and vasculogenic pRP-ED refractory to maximal medical treatment were divided into four equal groups treated with escalating BM-MNC doses (2×10(7), 2×10(8), 1×10(9), 2×10(9)). Tolerance was the primary endpoint. Secondary endpoints were the effects on erectile function and penile vascularization at 6 mo, as assessed using the International Index of Erectile Function-15 and Erection Hardness Scale questionnaires, and color duplex Doppler ultrasound. We measured the peak systolic velocity in cavernous arteries and assessed endothelial function using the penile nitric oxide release test. No serious side effects occurred. At 6 mo versus baseline, significant improvements of intercourse satisfaction (6.8±3.6, 3.9±2.5, p=0.044) and erectile function (17.4±8.9, 7.3±4.5, p=0.006) domains of the International Index of Erectile Function-15 and Erection Hardness Scale (2.6±1.1, 1.3±0.8, p=0.008) were observed in the total population. Spontaneous erections showed significantly greater improvement with the higher doses. Clinical benefits were associated with improvement of peak systolic velocity and of % penile nitric oxide release test and sustained after 1 yr. Our results need to be confirmed by phase 2 clinical trials.

Concepts: Clinical trial, Prostate cancer, Avicenna, Nitric oxide, Erectile dysfunction, Penis, Erection, Priapism


People with sickle cell disease (SCD) suffer from numerous acute complications that can result in multiple hospitalizations and emergency department (ED) and outpatient care visits. Priapism, a prolonged unwanted erection of the penis not due to sexual stimulation, is a serious complication among males with SCD. Variations in estimates of prevalence make it difficult to accurately assess the burden of this complication of SCD. We analyzed data from the Nationwide Emergency Department Sample (NEDS), a product of the Healthcare Cost and Utilization Project, for the years 2006 through 2010 to measure the numbers of ED visits and to examine patterns of subsequent hospitalizations associated with priapism among male patients with SCD. We find that among ED visits associated with males with SCD, those prompted by priapism are more likely to result in hospitalization than are those associated with pain.

Concepts: Medicine, Hospital, United States, Urgent care, Sickle-cell disease, Ejaculation, Penis, Priapism


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. As 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 + 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 measurement of prolonged erections following cessation of electrical stimulation of the cavernous nerve. Penile tissue was processed and analyzed by reversed-phase liquid chromatography tandem mass spectrometry. 1279 total proteins were identified and quantified by spectral counting, 46 of which were downregulated and 110 of which were upregulated in NOS1/3-/- vs. 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-/- penis which represent potential mechanisms contributing to priapism secondary to low NO bioavailability.

Concepts: Protein, Signal transduction, Nitric oxide, Erectile dysfunction, Penis, Erection, Sexual arousal, Priapism