Anterior ischemic optic neuropathy and stroke with use of PDE-5 inhibitors for erectile dysfunction: cause or coincidence?

The Impact of Systemic Medications on Retinal Function

This study will provide a thorough review of systemic (and select intravitreal) medications, along with illicit drugs that are capable of causing various patterns of retinal toxicity. The diagnosis is established by taking a thorough medication and drug history, and then by pattern recognition of the clinical retinal changes and multimodal imaging features. Examples of all of these types of toxicity will be thoroughly reviewed, including agents that cause retinal pigment epithelial disruption (hydroxychloroquine, thioridazine, pentosan polysulfate sodium, dideoxyinosine), retinal vascular occlusion (quinine, oral contraceptives), cystoid macular edema/retinal edema (nicotinic acid, sulfa-containing medications, taxels, glitazones), crystalline deposition (tamoxifen, canthaxanthin, methoxyflurane), uveitis, miscellaneous, and subjective visual symptoms (digoxin, sildenafil). The impact of newer chemotherapeutics and immunotherapeutics (tyrosine kinase inhibitor, mitogen-activated protein kinase kinase, checkpoint, anaplastic lymphoma kinase, extracellular signal-regulated kinase inhibitors, and others), will also be thoroughly reviewed. The mechanism of action will be explored in detail when known. When applicable, preventive measures will be discussed, and treatment will be reviewed. Illicit drugs (cannabinoids, cocaine, heroin, methamphetamine, alkyl nitrite), will also be reviewed in terms of the potential impact on retinal function.

Effects of systemic drugs on the development and progression of age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of severe loss of central vision among people over 50. The pathophysiology of the disease is multifactorial and can be attributed to genetics, aging, inflammation, environmental factors, and lifestyle factors including smoking, diet, obesity, and alcohol consumption. While there is no treatment for dry AMD, the current standard treatment for wet AMD is an intraocular injection of anti-vascular endothelial growth factor-an effective, yet expensive, therapy that requires ongoing treatment. As the aging population continues to grow, and AMD diagnoses continue to rise, new treatments should be explored to reduce vision complications and decrease treatment burdens. Many systemic conditions have progressive pathological changes that may affect AMD, particularly those affecting systemic vasculature like diabetes and cardiovascular status. Consequently, systemic drugs used to treat coexistent systemic diseases may influence some of the pathogenic mechanisms of AMD and lead its progression or delay. In this review we explore the current literature to summarize the findings of the reported effects of antihypertensive, immunosuppressants, cholesterol lowering agents, nonsteroidal anti-inflammatory drugs, dopamine precursors, hypoglycemic agents, and anticoagulants on AMD.

Exosomes derived from miR-301a-3p-overexpressing adipose-derived mesenchymal stem cells reverse hypoxia-induced erectile dysfunction in rat models

Background

Erectile dysfunction (ED) has often been observed in patients with obstructive sleep apnea (OSA). Research on adipose-derived mesenchymal stem cell (ADSC)-derived exosomes has shown that they have significant therapeutic effects in many diseases including ED.

Methods

In this study, ED was induced in Sprague Dawley (SD) rats using chronic intermittent hypoxia (CIH) exposure. CIH-mediated influences were then measured in the corpus cavernous smooth muscle cells (CCSMCs).

Results

Our data showed that miR-301a-3p-enriched exosome treatment significantly recovered erectile function in rats and CCSMCs by promoting autophagy and inhibiting apoptosis. The treatment also significantly recovered the level of alpha smooth muscle actin (α-SMA) in rats and CCSMCs. Bioinformatics predicted that phosphatase and tensin homolog (PTEN) and Toll-like receptor 4 (TLR4) might be targets of miR-301a-3p.

Conclusions

Our results indicate that PTEN-overexpression vectors or TLR4-overexpression vectors reverse the therapeutic effects achieved by miR-301a-3p in CCSMCs indicating that PTEN/hypoxia-inducible factor-1 alpha (HIF-1α) and TLR4 signaling pathways play key roles in the progression of ED. The findings in this study suggest that miR-301a-3p should be considered a new therapeutic target for treating ED associated with OSA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02161-8.

Increased bioavailability of cyclic guanylate monophosphate prevents retinal ganglion cell degeneration

The nitric oxide - guanylyl cyclase-1 - cyclic guanylate monophosphate (NO-GC-1-cGMP) pathway has emerged as a potential pathogenic mechanism for glaucoma, a common intraocular pressure (IOP)-related optic neuropathy characterized by the degeneration of retinal ganglion cells (RGCs) and their axons in the optic nerve. NO activates GC-1 to increase cGMP levels, which are lowered by cGMP-specific phosphodiesterase (PDE) activity. This pathway appears to play a role in both the regulation of IOP, where reduced cGMP levels in mice leads to elevated IOP and subsequent RGC degeneration. Here, we investigated whether potentiation of cGMP signaling could protect RGCs from glaucomatous degeneration. We administered the PDE5 inhibitor tadalafil orally (10 mg/kg/day) in murine models of two forms of glaucoma - primary open angle glaucoma (POAG; GC-1^-/- mice) and primary angle-closure glaucoma (PACG; Microbead Occlusion Model) - and measured RGC viability at both the soma and axon level. To determine the direct effect of increased cGMP on RGCs in vitro, we treated axotomized whole retina and primary RGC cultures with the cGMP analogue 8-Br-cGMP. Tadalafil treatment increased plasma cGMP levels in both models, but did not alter IOP or mean arterial pressure. Nonetheless, tadalafil treatment prevented degeneration of RGC soma and axons in both disease models. Treatment of whole, axotomized retina and primary RGC cultures with 8-Br-cGMP markedly attenuated both necrotic and apoptotic cell death pathways in RGCs. Our findings suggest that enhancement of the NO-GC-1-cGMP pathway protects the RGC body and axon in murine models of POAG and PACG, and that enhanced signaling through this pathway may serve as a novel glaucoma treatment, acting independently of IOP.

The nitric oxide-guanylate cyclase pathway and glaucoma

Glaucoma is a prevalent optic neuropathy characterized by the progressive dysfunction and loss of retinal ganglion cells (RGCs) and their optic nerve axons, which leads to irreversible visual field loss. Multiple risk factors for the disease have been identified, but elevated intraocular pressure (IOP) remains the primary risk factor amenable to treatment. Reducing IOP however does not always prevent glaucomatous neurodegeneration, and many patients progress with the disease despite having IOP in the normal range. There is increasing evidence that nitric oxide (NO) is a direct regulator of IOP and that dysfunction of the NO-Guanylate Cyclase (GC) pathway is associated with glaucoma incidence. NO has shown promise as a novel therapeutic with targeted effects that: 1) lower IOP; 2) increase ocular blood flow; and 3) confer neuroprotection. The various effects of NO in the eye appear to be mediated through the activation of the GC- guanosine 3:5'-cyclic monophosphate (cGMP) pathway and its effect on downstream targets, such as protein kinases and Ca²⁺ channels. Although NO-donor compounds are promising as therapeutics for IOP regulation, they may not be ideal to harness the neuroprotective potential of NO signaling. Here we review evidence that supports direct targeting of GC as a novel pleiotrophic treatment for the disease, without the need for direct NO application. The identification and targeting of other factors that contribute to glaucoma would be beneficial to patients, particularly those that do not respond well to IOP-dependent interventions.

Newer phosphodiesterase inhibitors: comparison with established agents

Erectile dysfunction is defined as the consistent or recurrent inability to attain or maintain penile erection sufficient for sexual performance. Self-reported erectile dysfunction has increased significantly as men seek effective therapy, such as oral phosphodiesterase 5 inhibitors (PDE5i). PDE5i are now the drugs of choice in the initial therapy of erectile dysfunction. This review compares the currently available PDE5i with the second-generation PDE5i, which are soon to be available.

Male sexual disorders following stroke: an overview

Stroke is one of the leading causes of death and disability throughout the world. Although physical and cognitive impairments after stroke have been well studied, little information is known about one of the crucial aspect of the quality of life of stroke patients, namely, sexual functioning and satisfaction. Poststroke sexual dysfunctions seem to be very common since in men affected by stroke, a decline in libido and poor or tailed erection and ejaculation are frequently observed. Sexual disorders after stroke are thought to be due to multiple etiologies, including both organic (i.e., lesion localization, premorbid medical conditions, and medications) and psychosocial (i.e., fear of recurrences, loss of self-esteem, role changes, anxiety, and depression). Thus, exploration in sexual dysfunctions and sexual counseling by trained professionals should be a part of stroke rehabilitation. The aim of this review is to evaluate the burden of stroke on sexual function taking into account the complex interaction between neurological, psychological, and relational factors.

Intracoital subfoveal hemorrhage after tadalafil (cialis) premedication: a case report

PURPOSE

The purpose of this study is to report the first case, to our knowledge, of intracoital subfoveal hemorrhage occurring 1 hour after tadalafil premedication in a patient with previously undiagnosed retinal angiomatous proliferation and erectile dysfunction.

METHODS

This is an interventional case report. The patient underwent Snellen vision acuity measurement, anterior and posterior segment biomicroscopy, and indirect ophthalmoscopy. Optical coherence tomography, fluorescein angiography, and indocyanine green angiography were also performed as needed. Recombinant tissue plasminogen activator 100 μg/0.1 mL and 0.3 mL pure SF6 gas were injected in the vitreous on presentation. Four days later, the patient received 1.25 mg/0.1 mL of intravitreal bevacizumab.

RESULTS

One day after recombinant tissue plasminogen activator and gas injection, visual acuity rose to 20/60-2. A week later, visual acuity was unchanged, and the subretinal hemorrhage displaced from the foveola. Optical coherence tomography showed a marked regression of submacular thickening.

CONCLUSION

Despite strict time correlation, the submacular hemorrhage cannot be unequivocally attributed to tadalafil assumption because many other risk factors are to be considered: the Valsalva maneuver above all. Nonetheless, a suspicion should be raised, at least as a cofactor, given the drug mechanism of action and the report of vascular abnormalities bleeding in the literature, including cerebral arterovenous malformation and epistaxis. Caution should be exercised in the prescription of phosphodiesterase type 5 inhibitors to patients with known vascular abnormalities including retinal and choroidal abnormalities: retinal angiomatous proliferation, classic and occult neovascularization of any origin, and also, possibly, hemangioma.

Nonarteritic anterior ischaemic optic neuropathy

PURPOSE OF REVIEW

There have been many reports in recent literature concerning the use of scanning laser polarimetry, Heidelberg retinal tomography and optical coherence topography in assessing the optic nerve and peripapillary nerve fibre layer. It is important to assess the validity of new equipment and see whether this has improved our understanding of the disease. There are also reports about possible association of nonarteritic anterior ischaemic optic neuropathy with cataract surgery and phosphodiesterase type-5 inhibitors. This review attempts to look at some of the techniques used and possible associations with nonarteritic anterior ischaemic optic neuropathy.

RECENT FINDINGS

Scanning laser polarimetry, Heidelberg retinal tomography and optical coherence tomography have been helpful in quantifying optic nerve and peripapillary retinal nerve fibre layer defects, with different efficacy and limitations. Although these confirm the damage to retinal nerve fibre layer beyond what is detected by standard visual field examination, the effect of cataract surgery and phosphodiesterase type-5 inhibitors remains to be further studied on a larger scale. The few experimental treatments for nonarteritic anterior ischaemic optic neuropathy also need further confirmatory studies.

SUMMARY

More studies are required to evaluate the benefits of new imaging methods. The availability of a primate model may provide clues to assessing experimental treatments for nonarteritic anterior ischaemic optic neuropathy.