Sildenafil improves sexual functioning in premenopausal women with type 1 diabetes who are affected by sexual arousal disorder: a double-blind, crossover, placebo-controlled pilot study

The impact of diabetes mellitus on female sexual well-being

For women, the risk for developing diabetes mellitus is reaching epidemic levels. As a result of the impact of diabetes on multiple body systems, women may suffer from medical and psychologic problems, including sexual dysfunction. It is difficult to separate sexual response from the many emotional and other contributing factors that may influence a relationship. Therefore, it is vital that clinicians address the issue of sexuality with their female diabetic patients. This article provides a brief review of the literature, followed by a discussion addressing the proper approach for sexual dysfunction screening. Finally, this article considers some of the current and future treatment modalities that can be used to enhance sexual functioning in female diabetics with impaired sexual function.

Blockade of phosphodiesterase Type 5 enhances rat neurohypophysial excitability and electrically evoked oxytocin release

Phosphodiesterase type 5 (PDE5) acts specifically on cyclic guanosine monophosphate (cGMP) and terminates cGMP-mediated signalling. PDE5 has a well established role in vascular smooth muscle, where specific inhibitors of PDE5 such as sildenafil correct erectile dysfunction by augmenting cGMP-mediated vascular relaxation. However, the role of PDE5 outside of the vasculature has received little attention. The present study tested PDE5 inhibitors on the cGMP-mediated modulation of K(+) channels in the neurohypophysis (posterior pituitary). Photolysis of caged-cGMP enhanced current through Ca(2+)-activated K(+) channels, and this enhancement recovered in about 2 min. Sildenafil essentially eliminated this recovery, suggesting that the reversal of K(+) current enhancement depends on cGMP breakdown. Activation of nitric oxide synthase during trains of activity in pituitary nerve terminals enhances excitability. When trains of stimulation were applied at regular intervals, sildenafil enhanced the excitability of neurohypophysial nerve terminals and increased the action potential firing probability. T-1032, a compound with high specificity for PDE5 over PDE6, had a similar action. Voltage imaging in intact neurohypophysis with a voltage sensitive absorbance dye showed that T-1032 reduced the failure of propagating action potentials during trains of activity. This indicates that PDE5 activity limits action potential propagation in neurohypophysial axons. Immunoassay of oxytocin, a neuropeptide hormone secreted by the posterior pituitary, demonstrated that sildenafil increased electrically evoked release. Thus, PDE5 plays an important role in the regulation of neurohypophysial function, and blockade of this enzyme can enhance the use-dependent facilitation of neurohypophysial secretion.

Clitoral Blood Flow Changes After Surgery for Stress Urinary Incontinence: Pilot Study on TVT Versus TOT Procedures

OBJECTIVES

To study the effects of mini-invasive surgery using the tension-free vaginal tape (TVT) procedure and the transobturator tape (TOT) procedure in modifying clitoral blood flow in women affected by stress urinary incontinence.

METHODS

The setting of the prospective open clinical study was the Urogynecologic Service of the Department of Microbiological and Gynecological Science, University of Catania School of Medicine (Catania, Italy). A total of 105 women underwent surgery; 42 (mean age 52.8 years) and 63 (mean age 53.9 years) were treated with TVT and TOT, respectively. Each woman underwent translabial color Doppler ultrasonography to measure the resistance index, pulsatility index, peak systolic velocity, and end-diastolic velocity of the clitoral arteries, before and 6 months postoperatively.

RESULTS

In the TVT group, the mean pulsatility index and mean peak systolic velocity were significantly lower and the mean resistance index was significantly greater compared with the pretreatment values (P <0.5). In the TOT group, each color Doppler measurement was similar to that obtained at baseline (P = NS).

CONCLUSIONS

The different vaginal approach for these two surgical methods influenced clitoral blood flow. Our data could add new information about sexual behavior after incontinence treatment, particularly the impact of clitoral blood flow changes.

PDE5 inhibitors beyond erectile dysfunction

The phosphodiesterase type-5 (PDE5) inhibitors sildenafil, vardenafil and tadalafil are widely used first-line therapy for erectile dysfunction (ED). Since the advent of sildenafil in 1998, more than 40 million men worldwide have been successfully treated with these compounds. The safety and high tolerability of PDE5 inhibitors make them an attractive tool to investigate further physiological functions of PDE5, for example the modulation of intracellular cyclic GMP (cGMP) pools. As cGMP is a key component of intracellular signaling this may provide novel therapeutic opportunities beyond ED even for indications in which chronic administration is necessary. The approval of sildenafil for the treatment of pulmonary hypertension in 2005 was a notable success in this area of research. A number of other potential new indications are currently in various phases of preclinical research and development. In recent years, extensive but very heterogeneous information has been published in this field. The aim of this review is to summarize existing preclinical and clinical knowledge and critically discuss the evidence to support potential future indications for PDE5 inhibitors.

Sexual dysfunction in the medically ill

Common in the medically ill, sexual dysfunction results from disruption of one or more stages of the sexual response cycle. Increased understanding of sexual pathophysiology and the psychosocial forces whereby diseases impede normal function promotes more informed treatment choices. This review focuses on the pathophysiology, impact, and treatment options of sexual dysfunction in men and women with spinal cord injuries, multiple sclerosis, dementia, hypertension, heart disease, stroke, cancer, and HIV/AIDS.

[Sexuality and pharmacotherapy. Medication-induced disorders of sexual response and pharmacotherapeutic options for the treatment of sexual dysfunctions]

This contribution addresses two different areas of the complex relationship between pharmacotherapy and sexual function and dysfunction in men and women. As many impairments of sexual function are caused by side effects of medications, particularly psychotropic drugs, the first part of the paper describes substances and mechanisms often related to sexual dysfunction with a special focus on antidepressants and neuroleptics. While serotonin reuptake inhibitors entail a high risk of sexual dysfunction, it is often difficult to differentiate the negative impact of the drug from the impairment caused by the mental disorder itself. Ways to deal with these dysfunctions and remedial measures are discussed. In the second section, current pharmacological treatments for female and male sexual dysfunctions are reviewed. While there is no approved pharmacotherapy with established efficacy for female sexual dysfunction with the possible exception of the transdermal testosterone patch for surgically menopausal women, effective pharmacological therapies are available for male erectile disorders. In addition, testosterone substitution is the treatment of choice for hypoactive sexual desire disorders caused by hypogonadism. As sexual dysfunctions are often caused by a mixture of psychological and organic factors, treatment strategies combining pharmacological options and sex therapy are advocated.

Sexual dysfunction in men and women with endocrine disorders

Endocrine disease frequently interrupts sexual function, and sexual dysfunction may signal serious endocrine disease. Diabetic autonomic neuropathy and endothelial dysfunction impair erectile function, and phosphodiesterase inhibition produces only moderate benefit. The effect of diabetes on women's sexual function is complex: the most consistent finding is a correlation between sexual dysfunction and depression. Reductions in testosterone level in men are associated with low sexual desire and reduced nocturnal erections and ejaculate volume, all of which improve with testosterone supplementation. The age-dependent decline in testosterone production in men is not associated with precise sexual symptoms, and supplementation has not been shown to produce sexual benefit. In women, sexual dysfunction has not been associated with serum testosterone, but this may be confounded by limitations of assays at low concentrations and by the greater importance of intracellular production of testosterone in women than in men. Testosterone supplementation after menopause does improve some aspects of sexual function in women, but long-term outcome data are needed. More research on the sexual effects of abnormal adrenal and thyroid function, hyperprolactinaemia, and metabolic syndrome should also be prioritised. We have good data on local management of the genital consequences of oestrogen lack, but need to better understand the potential role of systemic oestrogen supplementation from menopause onwards in sexually symptomatic women.