Effect of a Local Delivery of Triiodothyronine (T3) Within Neuroregenerative Guide on Recovery of Erectile Function in a Rat-Model of Cavernous Nerve Injury

Global research trends on the links between prostate cancer and erectile dysfunction between 2003 and 2023: A bibliometrics and visualized study

Background

The incidence of prostate cancer (PC) has increased in recent years. Erectile dysfunction (ED) after prostate cancer treatment has aroused extensive attention. Bibliometric analysis was designed to investigate a systematic understanding of developments between PC and ED during the past 20 years.

Methods

Literatures on PC and ED were retrieved from the Web of Science Core Collection database (WoSCC). By using the VOS viewer and CiteSpace software to analysis the metrics of bibliometric literature, such as number of articles, journals, countries, institutions, authors, keywords and associated information. The number of publications per year was statistically analysed and plotted thorough Microsoft Office. In addition, Pajek software was used to adjust the visual map.

Results

A total of 2332 screened articles were included in the analysis. The Journal of Sexual Medicine, ranking first among the analysed journals, published 235 articles. The United States and Canada were leaders in PC and ED research. There is a need to strengthen inter-agency cooperation in this area of research on a global scale. Mulhall JP, as the most prolific author in this area of research, published 80 articles. And Rosen RC was the author with the most co-citated (693 co-citated). The main research focus on the prevention, treatment and management of ED after PC treatment in this field through the keyword analysis.

Conclusions

Research on PC and ED is expected to expand further worldwide. We found ED, as new sustainable treatment modalities, scientific postoperative management and psychological interventions for patients, may become the research hotspots and should be closely concerned in this study.

Wiring the ocular surface: A focus on the comparative anatomy and molecular regulation of sensory innervation of the cornea

The cornea is richly innervated with sensory nerves that function to detect and clear harmful debris from the surface of the eye, promote growth and survival of the corneal epithelium and hasten wound healing following ocular disease or trauma. Given their importance to eye health, the neuroanatomy of the cornea has for many years been a source of intense investigation. Resultantly, complete nerve architecture maps exist for adult human and many animal models and these maps reveal few major differences across species. Interestingly, recent work has revealed considerable variation across species in how sensory nerves are acquired during developmental innervation of the cornea. Highlighting such species-distinct key differences, but also similarities, this review provides a full, comparative anatomy analysis of sensory innervation of the cornea for all species studied to date. Further, this article comprehensively describes the molecules that have been shown to guide and direct nerves toward, into and through developing corneal tissue as the final architectural pattern of the cornea's neuroanatomy is established. Such knowledge is useful for researchers and clinicians seeking to better understand the anatomical and molecular basis of corneal nerve pathologies and to hasten neuro-regeneration following infection, trauma or surgery that damage the ocular surface and its corneal nerves.

Unique and overlapping effects of triiodothyronine (T3) and thyroxine (T4) on sensory innervation of the chick cornea

Multiple aspects of cornea development, including the innervation of the cornea by trigeminal axons, are sensitive to embryonic levels of thyroid hormone (TH). Although previous work showed that increased TH levels could enhance the rate of axonal extension within the cornea in a thyroxine (T4)-dependent manner, details underlying the stimulatory effect of TH on cornea innervation are unclear. Here, by examining the effects throughout all stages of cornea innervation of the two main THs, triiodothyronine (T3) and T4, we provide a more complete characterization of the stimulatory effects of TH on corneal nerves and begin to unravel the underlying molecular mechanisms. During development, trigeminal axons are initially repelled at the corneal periphery and encircle the cornea in a pericorneal nerve ring prior to advancing into the corneal stroma radially from all along the nerve ring. Overall, exogenous T3 led to pleiotropic effects throughout all stages of cornea innervation, whereas the effects of exogenous T4 was confined to timepoints following completion of the nerve ring. Specifically, exogenous T3 accelerated the formation of the pericorneal nerve ring. By utilizing in vitro neuronal explants studies we demonstrated that T3 acts as a trophic factor to directly stimulate trigeminal nerve growth. Further, exogenous T3 caused disorganized and precocious innervation of the cornea, accompanied by the downregulation of inhibitory Robo receptors that normally act to regulate the timing of nerve advancement into the Slit-expressing corneal tissues. Following nerve ring completion, the growth rate and branching behavior of nerves as they advanced into and through the cornea were found to be stimulated equally by T3 or T4. These stimulatory influences of T3/T4 over nerves likely arose as secondary consequences brought on by TH-mediated modulations to the corneal extracellular matrix. Specifically, we found that the levels of nerve-inhibitory keratan- and chondroitin-sulfate containing proteoglycans and associated sulfation enzymes were dramatically altered in the presence of exogenous T3 or T4. Altogether, these findings uncover new roles for TH on corneal development and shed insight into the mechanistic basis of both T3 and T4 on cornea innervation.

Stimulating effect of thyroid hormones in peripheral nerve regeneration: research history and future direction toward clinical therapy

Injury to peripheral nerves is often observed in the clinic and severe injuries may cause loss of motor and sensory functions. Despite extensive investigation, testing various surgical repair techniques and neurotrophic molecules, at present, a satisfactory method to ensuring successful recovery does not exist. For successful molecular therapy in nerve regeneration, it is essential to improve the intrinsic ability of neurons to survive and to increase the speed of axonal outgrowth. Also to induce Schwann cell phenotypical changes to prepare the local environment favorable for axonal regeneration and myelination. Therefore, any molecule that regulates gene expression of both neurons and Schwann cells could play a crucial role in peripheral nerve regeneration. Clinical and experimental studies have reported that thyroid hormones are essential for the normal development and function of the nervous system, so they could be candidates for nervous system regeneration. This review provides an overview of studies devoted to testing the effect of thyroid hormones on peripheral nerve regeneration. Also it emphasizes the importance of combining biodegradable tubes with local administration of triiodothyronine for future clinical therapy of human severe injured nerves. We highlight that the local and single administration of triiodothyronine within biodegradable nerve guide improves significantly the regeneration of severed peripheral nerves, and accelerates functional recovering. This technique provides a serious step towards future clinical application of triiodothyronine in human severe injured nerves. The possible regulatory mechanism by which triiodothyronine stimulates peripheral nerve regeneration is a rapid action on both axotomized neurons and Schwann cells.

Erectile dysfunction after radical prostatectomy: prevalence, medical treatments, and psychosocial interventions

PURPOSE OF REVIEW

This review will discuss erectile dysfunction in prostate cancer patients following radical prostatectomy . It will focus on the prevalence and current treatments for erectile dysfunction as well as the emotional impact of erectile dysfunction and the current psychosocial interventions designed to help patients cope with this side effect.

RECENT FINDINGS

Although there is a large discrepancy in prevalence rates of erectile dysfunction after radical prostatectomy, several recent studies have cited rates as high as 85%. The concept of 'penile rehabilitation' is now the standard of practice to treat erectile dysfunction following radical prostatectomy. However, many men avoid seeking help or utilizing erectile dysfunction treatments. This avoidance is related to the shame, frustration, and distress many men with erectile dysfunction and their partners experience. Recent psychosocial interventions have been developed to facilitate the use of treatments and help men cope with erectile dysfunction. These interventions have shown initial promise, however, continued intervention development is needed to reduce distress and improve long-term erectile function outcomes.

SUMMARY

Erectile dysfunction is a significant problem following prostate cancer surgery. Although there are effective medical treatments, the development of psychosocial interventions should continue to evolve to maximize the assistance we can give to men and their partners.

Decreased thyroid hormone signaling accelerates the reinnervation of the optic tectum following optic nerve crush in adult zebrafish

The regenerative capacity of the adult mammalian central nervous system (CNS) is poor and finding ways to stimulate long distance axonal regeneration in humans remains a challenge for neuroscientists. Thyroid hormones, well known for their key function in CNS development and maturation, more recently also emerged as molecules influencing regeneration. While several studies investigated their influence on peripheral nerve regeneration, in vivo studies on their role in adult CNS regeneration remain scarce. We therefore investigated the effect of lowering T3 signaling on the regeneration of the optic nerve (ON) following crush in zebrafish, a species where full recovery occurs spontaneously. Adult zebrafish were exposed to iopanoic acid (IOP), which lowered intracellular 3,5,3'-triiodothyronine (T3) availability, or to the thyroid hormone receptor β antagonist methylsulfonylnitrobenzoate (C1). Both treatments accelerated optic tectum (OT) reinnervation. At 7days post injury (7dpi) there was a clear increase in the biocytin labeled area in the OT following anterograde tracing as well as an increased immunostaining of Gap43, a protein expressed in outgrowing axons. This effect was attenuated by T3 supplementation to IOP-treated fish. ON crush induced very limited cell death and proliferation at the level of the retina in control, IOP- and C1-treated fish. The treatments also had no effect on the mRNA upregulation of the regeneration markers gap43, tub1a, and socs3b at the level of the retina at 4 and 7dpi. We did, however, find a correlation between the accelerated OT reinnervation and a more rapid resolution of microglia/macrophages in the ON and the OT of IOP-treated fish. Taken together these data indicate that lowering T3 signaling accelerates OT reinnervation following ON crush in zebrafish and that this is accompanied by a more rapid resolution of the inflammatory response.

Inside-out autologous vein grafts fail to restore erectile function in a rat model of cavernous nerve crush injury after nerve-sparing prostatectomy

Some autologous tissues can restore erectile function (EF) in rats after a resection of the cavernous nerve (CN). However, a cavernous nerve crush injury (CNCI) better reproduces ED occurring after a nerve-sparing radical prostatectomy (RP). The aim was to evaluate the effect on EF of an autologous vein graft after CNCI, compared with an artificial conduit. Five groups of rats were studied: those with CN exposure, exposure+vein, crush, crush+guide and crush+vein. Four weeks after surgery, the EF of rats was assessed by electrical stimulation of the CNs. The intracavernous pressure (ICP) and mean arterial pressure (MAP) were monitored during stimulations at various frequencies. The main outcome, that is, the rigidity of the erections, was defined as the ICP/MAP ratio. At 10 Hz, the ICP/MAP ratios were 41.8%, 34.7%, 20.9%, 33.9% and 20.5%, respectively. The EF was significantly lower in rats if the CNCI was treated with a vein graft instead of an artificial guide. Contrary to cases of CN resection, autologous vein grafts did not improve EF after CNCI. In terms of clinical use, the study suggests to limit an eventual use of autologous vein grafts to non-nerve-sparing RPs.

Role of thyroid hormones in different aspects of nervous system regeneration in vertebrates

Spontaneous functional recovery from injury in the adult human nervous system is rare and trying to improve recovery remains a clinical challenge. Nervous system regeneration is a complicated sequence of events involving cell death or survival, cell proliferation, axon extension and remyelination, and finally reinnervation and functional recovery. Successful recovery depends on the cell-specific and time-dependent activation and repression of a wide variety of growth factors and guidance molecules. Thyroid hormones (THs), well known for their regulatory role in neurodevelopment, have recently emerged as important modulators of neuroregeneration. This review focuses on the endogenous changes in the proteins regulating TH availability and action in different cell types of the adult mammalian nervous system during regeneration as well as the impact of TH supplementation on the consecutive steps in this process. It also addresses possible differences in TH involvement between different vertebrate classes, early or late developmental stages and peripheral or central nervous system. The available data show that THs are able to stimulate many signaling pathways necessary for successful neurogeneration. They however also suggest that supplementation with T4 and/or T3 may have beneficial or detrimental influences depending on the dose and more importantly on the specific phase of the regeneration process.

Penile rehabilitation after radical prostatectomy: what the evidence really says

The pathophysiology of erectile dysfunction after radical prostatectomy (RP) is believed to include neuropraxia, which leads to temporarily reduced oxygenation and subsequent structural changes in penile tissue. This results in veno-occlusive dysfunction, therefore, penile rehabilitation programmes focus on tissue oxygenation. Animal studies support the use of phosphodiesterase type 5 inhibitors (PDE5Is) after cavernous nerve damage but results from human studies are contradictory. The largest study to date found no long-term effect of either daily or on-demand PDE5I administration after RP compared with placebo. The effects of prostaglandin and vacuum erection devices are questionable and high-quality studies are lacking. Better documentation for current penile rehabilitation and/or better rehabilitation protocols are needed. One must be careful not to repeat the statement that penile rehabilitation improves erectile function after RP so many times that it becomes a truth even without the proper scientific backing.

Evolution in the concept of erection anatomy

PURPOSE

To review and to summarize the literature on anatomy and physiology of erection in the past three decades, especially the work done in our institution.

METHODS

A search of the PubMed database was performed using keywords erection, anatomy and erectile dysfunction (ED). Relevant articles were reviewed, analyzed and summarized.

RESULTS

Penile vascularisation and innervation vary substantially. Internal pudendal artery is the major source of penile blood supply, but a supralevator accessory pudendal artery that may originate from inferior vesical or obturator or external iliac arteries is not uncommon. Section of this artery during radical prostatectomy (RP) may adversely affect postoperative potency. Anastomoses between the supra and the infralevator arterial pathways are frequent. The cavernous nerves (CNs) contain parasympathetic and sympathetic nerve fibers and these nerves lie within leaves of the lateral endopelvic fascia. Anastomoses between the CNs and the dorsal nerve of the penis are common. Nitric oxide released from noradrenergic, noncholinergic neurotransmission of the CN and from the endothelium is the principal neurotransmitter-mediating penile erection. Interactions between pro-erectile and anti-erectile neurotransmitters are not completely defined. Finally, medial preoptic area and paraventricular nucleus are the key structures in the central control of sexual function and penile erection.

CONCLUSIONS

The surgical and functional anatomy of erection is complex. Precise knowledge of penile vascularisation and innervation facilitates treatment of ED especially after RP.