Dutasteride in the long-term management of stuttering priapism

Filamin A cooperates with the androgen receptor in preventing skeletal muscle senescence

Aging induces a slow and progressive decrease in muscle mass and function, causing sarcopenia. Androgens control muscle trophism and exert important anabolic functions through the binding to the androgen receptor. Therefore, analysis of the androgen receptor-mediated actions in skeletal muscle might provide new hints for a better understanding of sarcopenia pathogenesis. In this study, we report that expression of the androgen receptor in skeletal muscle biopsies from 20 subjects is higher in young, as compared with old subjects. Co-immunoprecipitation experiments reveal that the androgen receptor is complexed with filamin A mainly in young, that in old subjects. Therefore, we have in depth analyzed the role of such complex using C2C12 myoblasts that express a significant amount of the androgen receptor. In these cells, hormone stimulation rapidly triggers the assembly of the androgen receptor/filamin A complex. Such complex prevents the senescence induced by oxidative stress in C2C12 cells, as disruption of the androgen receptor/filamin A complex by Rh-2025u stapled peptide re-establishes the senescent phenotype in C2C12 cells. Simultaneously, androgen stimulation of C2C12 cells rapidly triggers the activation of various signaling effectors, including Rac1, focal adhesion kinase, and mitogen-activated kinases. Androgen receptor blockade by bicalutamide or perturbation of androgen receptor/filamin A complex by Rh-2025u stapled peptide both reverse the hormone activation of signaling effectors. These findings further reinforce the role of the androgen receptor and its extranuclear partners in the rapid hormone signaling that controls the functions of C2C12 cells. Further investigations are needed to promote clinical interventions that might ameliorate muscle cell function as well the clinical outcome of age-related frailty.

Epidemiology and treatment of priapism in sickle cell disease

Ischemic priapism is a common but underrecognized morbidity affecting about 33% of adult men with sickle cell disease (SCD). The onset of priapism occurs in the prepubertal period and tends to be recurrent with increasing age. Significantly, priapism is associated with an unrecognized high burden of mental duress and sexual dysfunctions. The diagnosis of priapism is clinical. Many episodes of priapism will resolve spontaneously, but when an episode lasts longer than 4 hours, the episode is considered a urologic emergency requiring quick intervention with either corporal aspiration or shunt surgery. Only 3 randomized clinical trials (stilbesterol, ephedrine or etilefrine, and sildenafil) have been conducted for secondary priapism prevention in SCD. All 3 trials were limited with small sample sizes, selection biases, and inconclusive results after completion. The current molecular understanding of the pathobiology of priapism suggests a relative nitric oxide (NO) deficiency secondary to chronic hemolysis in SCD and associated phosphodiesterase type 5 dysregulation. We posit an increase in NO levels will restore the normal homeostatic relationship between voluntary erection and detumescence. Currently, 2 randomized phase 2 trials (1 double-blind, placebo-controlled trial and 1 open-label, single-arm intervention) are being conducted for secondary priapism prevention in men at high risk for recurrent priapism (NCT03938454 and NCT05142254). We review the epidemiology and pathobiology of priapism, along with mechanistic therapeutic approaches for secondary prevention of priapism in SCD.

Update on Treatment Options for Stuttering Priapism

Purpose of Review

There is a paucity of peer-reviewed evidence to guide medical management of stuttering priapism. The purpose of this review is to summarize the current understanding regarding the pathophysiology of priapism and management options for stuttering priapism.

Recent Findings

Conducting large-scale, randomized, placebo-controlled trials that elucidate the optimal treatment of stuttering priapism is challenging. Therefore, recent treatment guidelines are based upon small case series, retrospective studies, and expert opinions. Nonetheless, multiple compounds from various drug classes have shown promise in treating stuttering priapism, and a few pharmacotherapies such as Crizanlizumab are currently under active investigation.

Summary

Stuttering priapism is an under-investigated disorder with a complex pathophysiology. Currently, there is no wildly adopted universal therapeutic strategy. Further research is warranted to identify the appropriate treatment of stuttering priapism and to determine the long-term side effects of current pharmacotherapies.

Stuttering Priapism in a Dog—First Report

Simple Summary

A 5-year-old recently castrated male Doberman dog presented for prolonged erection of one week’s duration with associated pain and dysuria. This was the fourth episode within a year. Each episode was associated with an unusual event, which was stressful for the dog. Castration performed two months prior to the final episode did not prevent recurrence. Due to tissue necrosis, penile amputation and urethrostomy had to be performed. To our knowledge, this case is the first report of a stuttering priapism in a dog. Stuttering priapism, also called recurrent or intermittent priapism, is a particular type of ischemic priapism described in humans that is characterized by repeated episodes of prolonged erections.

Abstract

A 5-year-old recently castrated male Doberman dog presented for prolonged erection of one week’s duration with associated pain and dysuria. This was the fourth episode within a year. Each episode was associated with an unusual event, which was stressful for the dog. Castration performed two months prior to the final episode did not prevent recurrence. Due to tissue necrosis, penile amputation and urethrostomy had to be performed. The dog recovered fully. Prolonged erection that persists beyond or that is unrelated to sexual stimulation is called “priapism”. This term refers to the Greek god Priapus, a god of fertility, memorialized in sculptures for his giant phallus. In humans, depending on the mechanism involved, priapism is classified as nonischemic or ischemic. Because prognosis and treatment are different, priapism must be determined to be nonischemic or ischemic. Nonischemic priapism is a rare condition observed when an increase in penile arterial blood flow overwhelms the capacity of venous drainage; it is often associated with penile trauma, and does not require medical intervention. Ischemic priapism is associated with decreased venous return. In humans, ischemic priapism accounts for 95% of cases, the majority of which are idiopathic. Ischemic priapism is a urological emergency; simple conservative measures such as aspiration of blood from the corpora cavernosa and intracavernosal injection of an adrenergic agent are often successful. Stuttering priapism, also called recurrent or intermittent priapism, is a particular form of ischemic priapism reported in humans that is characterized by repetitive episodes of prolonged erections. Management consists of treating each new episode as an episode of acute ischemic priapism, and preventing recurrence with oral medications such as dutasteride and/or baclofen, gabapentin, or tadalafil. To the authors’ knowledge, this case is the first report of stuttering priapism in a dog.

An update on the management algorithms of priapism during the last decade

Priapism is a persistent penile erection lasting longer than 4 hours, that needs emergency management. This disorder can induce irreversible erectile dysfunction. There are three subtypes of priapism: ischemic, non-ischemic, and stuttering priapism. If the patient has ischemic priapism (IP) of less than 24-hours (h) duration, the initial management should be a corporal blood aspiration followed by instillation of phenylephrine into the corpus cavernosum. If sympathomimetic fails or the patient has IP from 24 to 48h, surgical shunts should be performed. It is recommended that distal shunts should be attempted first. If distal shunt failed, proximal, venous shunt, or T-shunt with tunneling could be performed. If the patient had IP for 48 to 72h, proximal and venous shunt or T-shunt with tunneling is indicated, if those therapies failed, a penile prosthesis should be inserted. Non-ischemic priapism (NIP) is not a medical emergency and many patients will recover spontaneously. If the NIP does not resolve spontaneously within six months or the patient requests therapy, selective arterial embolization is indicated. The goal of the management of a patient with stuttering priapism (SP) is the prevention of future episodes. Phosphodiesterase type 5 (PDE5) inhibitor therapy is considered an effective tool to prevent stuttering episodes but it is not validated yet. The management of priapism should follow the guidelines as the future erectile function is dependent on its quick resolution. This review briefly discusses the types, pathophysiology, and diagnosis of priapism. It will discuss an updated approach to treat each type of priapism.

Management of Priapism: 2021 Update

Priapism is defined as a persistent penile erection lasting more than 4 hours. Priapism is a rare condition but when present it requires prompt evaluation and definitive diagnosis. Priapism has 2 pathophysiologic subtypes: ischemic and nonischemic. Ischemic priapism accounts for a majority of cases reported. Ischemic priapism is a urologic emergency and requires intervention to alleviate pain and prevent irreversible damage to erectile tissues. This article highlights current guidelines and the contemporary literature on priapism.

Medical treatment of recurrent ischaemic priapism: a review of current molecular therapeutics and a new clinical management paradigm

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.