Neuroanatomical study of periprostatic nerve distributions using human cadaver prostate

In Situ-Sprayed Bioinspired Adhesive Conductive Hydrogels for Cavernous Nerve Repair

Cavernous nerve injury (CNI), resulting in erectile dysfunction (ED), poses a significant threat to the quality of life for men. Strategies utilizing conductive hydrogels have demonstrated promising results for the treatment of peripheral nerves with a large diameter (>2 mm). However, integrating convenient minimally invasive operation, antiswelling and immunomodulatory conductive hydrogels for treating small-diameter injured cavernous nerves remains a great challenge. Here, a sprayable adhesive conductive hydrogel (GACM) composed of gelatin, adenine, carbon nanotubes, and mesaconate designed for cavernous nerve repair is developed. Multiple hydrogen bonds provide GACM with excellent adhesive and antiswelling properties, enabling it to establish a conformal electrical bridge with the damaged nerve and aiding in the regeneration process. Additionally, mesaconate-loaded GACM suppresses the release of inflammatory factors by macrophages and promotes the migration and proliferation of Schwann cells. In vivo tests demonstrate that the GACM hydrogel repairs the cavernous nerve and restores erectile function and fertility. Furthermore, the feasibility of sprayable GACM in minimally invasive robotic surgery in beagles is validated. Given the benefits of therapeutic effectiveness and clinical convenience, the research suggests a promising future for sprayable GACM materials as advanced solutions for minimally invasive nerve repair.

Indications for nerve-sparing surgery for radical prostatectomy: Results from a single-center study

Purpose

To explore the clinical indications of using the nerve-sparing technique in radical prostatectomy.

Patients and methods

We retrospectively analyzed the clinical and pathological data of 101 patients who underwent radical prostatectomy (RP) at our institution. Twenty-five patients underwent open surgery, and 76 patients underwent laparoscopic surgery. The biochemical recurrence (BCR) rate was analyzed by the method of Kaplan–Meier. The distance between the ipsilateral neurovascular bundles (NVBs) and foci of prostate tumor (N-T distance) was measured in postoperative specimens. We defined the N-T distance >2 mm as the threshold to perform nerve-sparing (NS) in RP. Through logistic regression analysis, we determined the preoperative clinical indications for the nerve-sparing technique in RP.

Results

The average BCR-free survival time was 53.2 months in these 101 patients with RP, with the 3- and 5-year BCR-free rates being 87.9% and 85.8%, respectively. The N-T distance was measured in 184 prostate sides from postoperative specimens of 101 patients. Univariate analysis showed that the percent of side-specific biopsy cores with cancer (≥1/3), maximum tumor length in biopsy core (≥5 mm), average percent involvement of each positive core (≥50%), PI-RADS score, and prostate MP-MRI imaging (extra-capsular extension) were associated with the N-T distance (p < 0.003). Furthermore, the percent of side-specific biopsy cores with cancer (≥1/3) (OR = 4.11, p = 0.0047) and prostate MP-MRI imaging (extra-capsular extension) (OR = 3.92, p = 0.0061) were found to be statistically significant independent predictors of the N-T distance in multivariate analysis.

Conclusions

The clinical indications of nerve-sparing RP were <1/3 side-specific biopsy cores with cancer and no extra-capsular extension by prostate MP-MRI examination.

Loss of the Sympathetic Signal Produces Sterile Inflammation of the Prostate

Neural innervations exert essential roles in the prostate. However, spatial distribution and regulatory function of such neural inputs are incompletely characterized. Here, we exploited the advanced whole-tissue immunolabeling and optical clearing technique to assess the 3D anatomy of autonomic innervations in the mouse and human prostate for the first time. We observed that sympathetic and parasympathetic inputs in the mouse prostate remained unaffected during castration-induced tissue regression. However, the pharmacologic destruction of sympathetic innervations in the mouse prostate led to sterile inflammation of the tissue, mimicking the disease condition of chronic non-bacterial prostatitis. Also, the genetic ablation of sympathetic inputs produced a similar inflammatory response. Furthermore, we showed that treatment of the specific β2-adrenergic receptor agonists could effectively mitigate the prostate inflammation caused by such sympathetic loss. Together, these results have elucidated the new immunomodulatory function of the sympathetic signal via the β2-adrenergic receptor in prostate inflammatory disease.

Analysis of Spatial Dose-Volume Relationships and Decline in Sexual Function Following Permanent Brachytherapy for Prostate Cancer

OBJECTIVE

To explore relationships between dose to periprostatic anatomic structures and erectile dysfunction (ED) outcomes in an institutional cohort treated with prostate brachytherapy.

METHODS

The Sexual Health Inventory for Men (SHIM) instrument was administered for stage cT1-T2 prostate cancer patients treated with Pd-103 brachytherapy over a 10-year interval. Dose volume histograms for regional organs at risk and periprostatic regions were calculated with and without expansions to account for contouring uncertainty. Regression tree analysis clustered patients into ED risk groups.

RESULTS

We identified 115 men treated with definitive prostate brachytherapy who had 2 years of complete follow-up. On univariate analysis, the subapical region (SAR) caudal to prostate was the only defined region with dose volume histograms parameters significant for potency outcomes. Regression tree analysis separated patients into low ED risk (mean 2-year SHIM 20.03), medium ED risk (15.02), and high ED risk (5.54) groups. Among patients with good baseline function (SHIM ≥ 17), a dose ≥72.75 Gy to 20% of the SAR with 1 cm expansion was most predictive for 2-year potency outcome. On multivariate analysis, regression tree risk group remained significant for predicting potency outcomes even after adjustment for baseline SHIM and age.

CONCLUSION

Dose to the SAR immediately caudal to prostate was predictive for potency outcomes in patients with good baseline function. Minimization of dose to this region may improve potency outcomes following prostate brachytherapy.

Silibinin stimluates apoptosis by inducing generation of ROS and ER stress in human choriocarcinoma cells

Silibinin is a flavonolignan extracted from seeds of milk thistles. Traditionally, it has been used as a therapeutic agent for liver disorders, and now it is well-known for its anti-cancer effects. However, studies on anti-cancer effects of silibinin on choriocarcinoma are very limited. Therefore, we performed proliferation and apoptosis assays to determine effects of silibinin on the viability of human choriocarcinoma (JAR and JEG3) cells. Our results showed that silibinin significantly inhibited proliferation and induced apoptosis in both JAR and JEG3 cells, and significantly increased reactive oxygen species (ROS) and lipid peroxidation. Moreover, silibinin disrupted mitochondrial function by inducing permeabilization of mitochondrial membrane potential and calcium ion efflux in JAR and JEG3 cells. Furthermore, silibinin-induced apoptosis in choriocarcinoma cells via AKT, mitogen-activated protein kinases (MAPK) and unfolded protein response (UPR) signal transduction. Collectively, our results suggest that silibinin is a novel therapeutic agent or dietary supplement for management of human placental choriocarcinomas.

Influence of fractional anisotropy thresholds on diffusion tensor imaging tractography of the periprostatic neurovascular bundle and selected pelvic tissues: do visualized tracts really represent nerves?

Background Diffusion tensor imaging (DTI) tractography has recently been shown to successfully visualize periprostatic tracts allegedly representing the neurovascular bundle. Purpose To examine the impact of different fractional anisotropy (FA) thresholds on the results of DTI tractography in the male pelvis as well as to evaluate the resulting specificity for nerve tracts. Material and Methods Ten healthy male volunteers were examined at 3 Tesla. DTI tractography was performed based on seed points placed circularly around the prostate, in the rectoprostatic angle, the peripheral zone of the prostate, the sciatic nerve, and in addition the urinary bladder using FA thresholds of 0.20, 0.05, and 0.01. DTI tract number and DTI tract length measured with different FA thresholds were compared. ANOVA with repeated measures was used for statistics. Results DTI tract number and tract length were significantly dependent on FA thresholds. While a FA threshold of 0.20 visualized the typical distribution of DTI tracts in the sciatic nerve, a FA threshold of ≤0.05 was necessary to yield results visually mimicking the distribution of nerve tracts in the NVB. However, with such low FA thresholds even in the filled urinary bladder DTI tracts could be visualized. With FA thresholds of 0.20, the number and length of periprostatic DTI tracts did not differ from those measured within the prostate. Conclusion DTI tractography can be used to visualize DTI tracts periprostatically. However, one may doubt that these DTI tracts represent nerve tracts and that the periprostatic neurovascular bundle can be evaluated in a meaningful way with the current methods available.

Novel methods for mapping the cavernous nerves during radical prostatectomy

The cavernous nerves, which course along the surface of the prostate gland, are responsible for erectile function. During radical prostatectomy, urologists are challenged in preserving these nerves and their function. Cavernous nerves are microscopic and show variable location in different patients; therefore, postoperative sexual potency rates are widely variable following radical prostatectomy. A variety of technologies, including electrical and optical nerve stimulation, dye-based optical fluorescence and microscopy, spectroscopy, ultrasound and magnetic resonance imaging have all been used to study cavernous nerve anatomy and physiology, and some of these methods are also potential intraoperative methods for identifying and preserving cavernous nerves. However, all of these technologies have inherent limitations, including slow or inconsistent nerve responses, poor image resolution, shallow image depth, slow image acquisition times and/or safety concerns. New and emerging technologies, as well as multimodal approaches combining existing methods, hold promise for improved postoperative sexual outcomes and patient quality of life following radical prostatectomy.

Novel anatomical identification of nerve-sparing radical prostatectomy: fascial-sparing radical prostatectomy

Radical prostatectomy (RP) became a first choice of treatment for prostate cancer after the advance in nerve-sparing techniques. However, the difficult technical details still involved in nerve-sparing RP (nsRP) can invite unwanted complications. Therefore, learning to recognize key anatomical features of the prostate and its surrounding structures is crucial to further improve RP efficacy. Although the anatomical relation between the pelvic nerves and pelvic fascias is still under investigation, this paper characterizes the periprostatic fascias in order to define a novel fascial-sparing approach to RP (fsRP), which will help spare neurovascular bundles. In uroanatomic perspective, it can be stated that nsRP is a functional identification of the surgical technique while fsRP is an anatomic identification as well. The functional and oncological outcomes related to this novel fsRP are also reviewed.

Pathological confirmation of nerve-sparing types performed during robot-assisted radical prostatectomy (RARP)

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Incremental nerve-sparing techniques (NSTs) improve postoperative erectile function after robot-assisted radical prostatectomy (RARP). However, there are no studies to date that histologically confirm the surgeon intended NST. Thus, in the present study, we histologically confirmed that the surgeon performed the nerve preservation as his intended NSTs during RARP. Also, we found that there was more variability in fascia width outcome on the left side compared with the right. Therefore, when performing nerve preservation on the surgeon's non-dominant side, we need to pay more close attention.

OBJECTIVES

To confirm that the surgeon achieved true intended histological nerve sparing during robot-assisted radical prostatectomy (RARP) by studying RP specimens. To aid the novice robotic surgeon to develop the skills of RARP.

PATIENTS AND METHODS

Between June 2008 and May 2009, 122 consecutive patients underwent RARP by a single surgeon (K.K.B.). The degree of nerve sparing (wide resection [WR], interfascial nerve sparing [ITE-NS], intrafascial nerve sparing [ITR-NS]) on both sides was recorded. The posterior sectors of RP specimens from distal, mid, and proximal parts were evaluated. Fascia width (FW) of each position in RP specimens were compared across nerve-sparing types (NSTs). FW was recorded at 15 ° intervals (3-9 o'clock position), measured as the distance between the outermost prostate gland and surgical margin. The slides were reviewed by an experienced uropathologist who was 'blinded' to the NST.

RESULTS

In all, 93 men were included. The overall mean (sd) FW was the greatest in the order of WR, ITE-NS, and ITR-NS, at 2.42 (1.62), 1.71 (1.40) and 1.16 (1.08) mm, respectively (P < 0.001). FW was statistically significantly correlated with the surgical technique used. When the surgeon intended to perform various levels of nerve sparing, these were reflected in the FW. Interestingly, the left-side FW showed more variability than the right side. We suspect that this was a result of the surgeon's right-hand dominance. Erectile function (EF) recovery rate according to NST was 88.9%, 77.3%, 65.6%, 56.3%, and 0% in bilateral ITR-NS, ITR-NS/ITE-NS, bilateral ITE-NS, ITE-NS/WR, and bilateral WR, respectively. To further validate and confirm these preliminary findings, additional studies involving multicentre cohorts would be required.

CONCLUSIONS

The surgeon intended dissection and FW correlate, with ITR-NS providing the narrowest FW and the EF recovery rate was the highest in bilateral ITR-NS. There was more variability in FW outcome on the left side than the right. The novice robotic surgeon should consider this variability when performing RARP. It may have implications for technique improvement on nerve preservation for EF.