Intravenously engrafted human multilineage-differentiating stress-enduring (Muse) cells rescue erectile function after rat cavernous nerve injury

OBJECTIVE

To evaluate the effect of intravenous administration of human multilineage-differentiating stress-enduring (Muse) cells on rat postoperative erectile dysfunction (ED) with cavernous nerve (CN) injury without an immunosuppressant.

MATERIALS AND METHODS

Male Sprague-Dawley rats were randomised into three groups after CN crush injury. Either human-Muse cells, non-Muse mesenchymal stem cells (MSCs) (both 1.0 × 105 cells), or vehicle was infused intravenously at 3 h after CN injury without immunosuppressant. Erectile function was assessed by measuring intracavernous pressure (ICP) and arterial pressure (AP) during pelvic nerve electrostimulation 28 days after surgery. At 48 h and 28 days after intravenous infusion of Muse cells, the homing of Muse cells and non-Muse MSCs was evaluated in the major pelvic ganglion (MPG) after CN injury. In addition, expressions of C-X-C motif chemokine ligand (Cxcl12) and glial cell line-derived neurotrophic factor (Gdnf) in the MPG were examined by real-time polymerase chain reaction. Statistical analyses and comparisons among groups were performed using one-way analysis of variance followed by the Tukey test for parametric data and Kruskal-Wallis test followed by the Dunn-Bonferroni test for non-parametric data.

RESULTS

The mean (SEM) ICP/AP values at 28 days were 0.51 (0.02) in the Muse cell group, 0.37 (0.03) in the non-Muse MSC group, and 0.36 (0.04) in the vehicle group, showing a significant positive response in the Muse cell group compared with the non-Muse and vehicle groups (P = 0.013 and P = 0.010, respectively). In the MPG, Muse cells were observed to be engrafted at 48 h and expressed Schwann cell markers S100 (~46%) and glial fibrillary acidic protein (~24%) at 28 days, while non-Muse MSCs were basically not engrafted at 48 h. Higher gene expression of Cxcl12 (P = 0.048) and Gdnf (P = 0.040) was found in the MPG of the Muse group than in the vehicle group 48 h after infusion.

CONCLUSION

Intravenously engrafted human Muse cells recovered rat erectile function after CN injury in a rat model possibly by upregulating Cxcl12 and Gdnf.

Intravenous Administration of Human Muse Cells Ameliorates Deficits in a Rat Model of Subacute Spinal Cord Injury

Multilineage-differentiating stress-enduring (Muse) cells are newly established pluripotent stem cells. The aim of the present study was to examine the potential of the systemic administration of Muse cells as an effective treatment for subacute SCI. We intravenously administered the clinical product "CL2020" containing Muse cells to a rat model two weeks after mid-thoracic spinal cord contusion. Eight experimental animals received CL2020, and twelve received the vehicle. Behavioral analyses were conducted over 20 weeks. Histological evaluations were performed. After 20 weeks of observation, diphtheria toxin was administered to three CL2020-treated animals to selectively ablate human cell functions. Hindlimb motor functions significantly improved from 6 to 20 weeks after the administration of CL2020. The cystic cavity was smaller in the CL2020 group. Furthermore, larger numbers of descending 5-HT fibers were preserved in the distal spinal cord. Muse cells in CL2020 were considered to have differentiated into neuronal and neural cells in the injured spinal cord. Neuronal and neural cells were identified in the gray and white matter, respectively. Importantly, these effects were reversed by the selective ablation of human cells by diphtheria toxin. Intravenously administered Muse cells facilitated the therapeutic potential of CL2020 for severe subacute spinal cord injury.

Rupture of an adjacent cerebral aneurysm following the deployment of a Pipeline embolization device: illustrative case

BACKGROUND

Although the Pipeline embolization device (PED) is effective for intracranial aneurysm treatment, its impact on the surrounding vascular structure is unknown.

OBSERVATIONS

A 71-year-old woman was incidentally found to have a simultaneous large posterior communicating artery aneurysm and an ipsilateral small anterior choroidal artery aneurysm. She underwent flow diversion therapy for both aneurysms with a PED, but the distal shortening of the PED after deployment led to the exposure of the anterior choroidal artery aneurysm. Follow-up angiography revealed complete obliteration of the posterior communicating artery aneurysm, but the anterior choroidal artery aneurysm remained. Three years after the endovascular surgery, the patient experienced a subarachnoid hemorrhage due to the rupture of the anterior choroidal artery aneurysm. Retrospective analysis of angiographic images revealed a change in the vascular geometry surrounding the ruptured aneurysm after PED deployment; this was further accompanied by an increase in the flow velocity inside the aneurysm.

LESSONS

Because PED use might induce the adverse effects on the adjacent uncovered aneurysm by changing the vascular geometry and hemodynamic stress, a cautious therapeutic strategy, such as proper placement of the stent and using a longer and appropriate-sized PED, should be chosen when deploying the PED.

Direct Inspection with Dual Endoscope Technique via Bilateral Transforaminal Approach Leading to Complete Resection of Recurrent Colloid Cyst of the Third Ventricle

BACKGROUND

Although endoscopic approaches are widely used for resection of colloid cysts because of the lower invasiveness, removal of the recurrent colloid cyst is still challenging. Total removal is sometimes difficult to achieve with single-port endoscopy because of the restricted access and working space. To compensate for these limitations, the dual endoscope technique via the bilateral transforaminal approach was chosen.

CASE DESCRIPTION

A 34-year-old woman with recurrent colloid cyst of the third ventricle was admitted to our department. She had a history of endoscopic subtotal removal at another institution. Reoperation was scheduled and the endoscopic bilateral transforaminal approach was chosen to ensure total removal with minimum complication risk. After decompression, the cyst was retracted toward the third ventricle floor via the right foramen of Monro. Under direct inspection with an angled scope via the right foramen of Monro, the cyst attachment on the third ventricle roof was sharply dissected via the left foramen of Monro, resulting in total removal.

CONCLUSIONS

The dual endoscope technique via the bilateral transforaminal approach can achieve better surgical outcome by obtaining direct visualization of the cyst attachment. Although the indication should be limited, this approach can be considered especially for patients with recurrent lesions involving possible adhesion to vital structures.

Reducing Surgeon's Physical Stress in Minimally Invasive Neurosurgery

BACKGROUND AND STUDY AIMS

 Various minimally invasive approaches are used in neurosurgery. Surgeons must perform nondynamic fine movements in a narrow corridor, so specially designed surgical devices are essential. Unsophisticated instruments may pose potential hazards. The purpose of this study was to assess the factors associated with muscle fatigue during minimally invasive neurosurgery and to investigate whether physical stress can be reduced by refining the devices used.

MATERIAL AND METHODS

 Four physical aspects of a handpiece were investigated: torque of conduits (0.20, 0.28, and 0.37 kgf*cm), shape of hand grip (five types), angle of the nozzle (0, 20, and 40 degrees), and weight balance (neutral, proximal, and distal). To evaluate muscle fatigue, surface electromyography was recorded from the extensor carpi radialis muscle and flexor carpi radialis muscle during a geometric tracing task. The maximum voluntary contraction (MVC) of each muscle and %MVC (muscle contraction during a task/MVC × 100) were used as the indexes of muscle fatigue.

RESULTS

 The shape of the hand grip significantly reduced %MVC, which is associated with muscle fatigue. The torque of conduits and angle of the nozzle tended to reduce muscle fatigue but not significantly. Weight balance did not affect muscle fatigue. Based on these results, we made two refined models: model α (torque of conduits 0.2 kgf*cm, angle of nozzle 20 degrees, neutral balance, hand grip with a 2.9 × 2.0-cm oval section with angled finger rest), and model β (torque of conduits 0.2 kgf*cm, angle of nozzle 20 degrees, neutral balance, hand grip with a 2.9-cm round section with a curved finger rest). The %MVC was significantly decreased with both types (p < 0.05 and p < 0.01, respectively), indicating reduction of muscle fatigue.

CONCLUSIONS

 The geometrically refined surgical device can improve muscle load during surgery and reduce the surgeon's physical stress, thus minimizing the risk of complications.

Water Veil Effect to Control Splashing from the Pulsed Water Jet Device: Minimizing the Potential Risk of Dissemination Using Surgical Aspirators

OBJECTIVE

 Maximum resection with minimum damage to normal structures is required for a better clinical outcome. Several efficient surgical devices such as the Cavitron ultrasonic surgical aspirator are available. Our group developed the actuator-driven pulsed water jet (ADPJ) to dissect soft tissue with vessel preservation. Although these devices are very effective for resection, tumor seeding is a potential risk. The present study investigated the control of splashing during ADPJ use. We demonstrate the effect of additional water flow around the instrument tip to veil the splashing.

METHODS

 Pulsed water jet was ejected from the tip of the ADPJ nozzle. Effects of ADPJ parameters such as input voltage, suction pressure, and distance between the nozzle and the target (standoff distance) on the amount of splashing were analyzed. Methylene blue solution was ejected on photo paper, gelatin brain phantom, and porcine brain harvested and subsequently immersed into physiologic saline to quantify the amount of splashing.

RESULTS

 High-input voltage and a long standoff distance had significant correlations with large amounts of splashing (r > 0.5; p < 0.01). However, suction pressure had no correlation (r = 0.23). Additional water flow combined with the ADPJ decreased the amount of splashing. A high-speed camera recording revealed that the additional water flow formed a water veil that prevented droplet dispersion, as confirmed with experiments using the brain phantom and porcine brain, in which the irregularity and elasticity are specific.

CONCLUSIONS

 The veil effect of additional water flow is important to reduce splashing during ADPJ use and can minimize the potential risk of dissemination and enhance the safety of the ADPJ.

Radioimmunoassay for somatostatin receptor type 2

OBJECTIVE

To develop radioimmunoassay for somatostatin receptor type 2 (SSTR2) and search for its presence in certain rat tissues.

METHODS

Anti-SSTR2 antiserum has been raised in New Zealand white rabbits immunized with a conjugate of synthetic SSTR2 with bovine serum albumin. Radioiodination of SSTR2 was performed by chloramin T method followed by purification of radioiodinated material on Sephadex G-25 column.

RESULTS

The obtained antibody did not crossreact with SSTR1, SSTR3, SSTR4, SSTR5, hypothalamic hormones, pituitary hormones, neuropeptides or gut hormones. The assay was performed with a double antibody system. SSTR2 was extracted from the tissues with acid acetone. The dilution curve of acid acetone-extracts of rat hypothalamus in the radioimmunoassay system was parallel to the standard curve. The recovery of tissue SSTR2 was about 89 %, and the intra-assay and inter-assay variations were 4.9 % and 7.8 %, respectively. SSTR2 was found in the hypothalamus, cerebrum, cerebellum, pituitary, stomach and testis.

CONCLUSIONS

These data suggest that this assay system is suitable for the estimation of SSTR2 in the tissues.

Radioimmunoassay for hypocretin-2

OBJECTIVE

To develop radioimmunoassay for hypocretin-2 (Hcrt-2). And search for its presence in certain rat tissues.

METHODS

Anti-Hcrt-2 serum has been raised in New Zealand white rabbits immunized with a conjugate of synthetic Hcrt-2 with bovine serum albumin. Radioiodination of Hcrt-2 was performed by chloramine T method, followed by purification of radoiodinated material on Sephadex G-25 column.

RESULTS

The obtained antibody did not cross react with hypocretin-2, hypothalamic hormones, pituitary hormones, neuropeptides or gut hormones. The assay was performed with a double antibody system. Hcrt-2 was extracted from the tissues with acid acetone. The dilution curve of acid acetone extracts of rat hypothalamus in the radioimmunoassay system was parallel to the standard curve. The recovery of tissue Hcrt-2 was about 85 % and the intra-assay and inter-assay variation were 5.6 % and 8.0 %, respectively. Hcrt-2 was found in the hypothalamus, cerebrum, brain stem and testes.

CONCLUSIONS

The obtained data suggest that the assay system developed is suitable to measure Hcrt-2 in tissues and that Hcrt-2 is mainly found in the hypothalamus.

Distribution of thyrotropin releasing hormone receptor type 2 in rats: an immunohistochemical study

OBJECTIVE

To investigate the organ distribution of thyrotropin releasing hormone receptor (TRHR) type 2 in rats by immunohistochemical method.

METHODS

TRHR type 2 was identified immunohistochemically in the rat tissues using specific anti-TRHR antiserum raised in New Zealand white rabbits immunized with a conjugate of synthetic TRHR type 2 (5-23) with bovine serum albumin. Immunohistochemical analysis was performed by avidin-biotin complex method.

RESULTS

TRHR type 2 immunoreactivity was visualized in the central nervous system, anterior pituitary, gastric mucosa, Auerbach's and Meissner's nervous branch of the stomach, small intestine and colon, retina amd testis. Significant stain was detected in neural perikarya, axons and dendrites. When using antiserum preincubated with synthetic TRHR type 2(5-23) or anterior pituitary homogenates, no significant stain of anterior pituitary was detected.

CONCLUSIONS

These findings suggest that TRHR type 2 is widely distributed and that the method used is valuable in studying the distribution of TRHR type 2 in rats.

Nociceptin stimulates thyrotropin secretion in rats

Effects of nociceptin on thyrotropin (TSH) and thyrotropin-releasing hormone (TRH) secretion in rats were studied. Nociceptin (150 microgram/kg) was injected intravenously and rats were serially decapitated after the injection. The effects of nociceptin on TRH release from the hypothalamus and TSH release from the anterior pituitary in vitro were also investigated. TRH and thyroid hormones were measured by individual radioimmunoassays. TSH was determined by enzyme immunoassay. TRH contents in the hypothalamus decreased significantly after nociceptin injection, whereas plasma TRH concentrations showed no changes. Plasma TSH concentrations increased significantly in a dose-related manner. The TRH release from the hypothalamus was enhanced significantly in a dose-related manner with the addition of nociceptin. The TSH release from the anterior pituitary in vitro was not affected by the addition of nociceptin. The plasma thyroxine and 3,3',5-triiodothyronine levels did not change significantly after nociceptin administration. The inactivation of TRH by plasma or hypothalamus in vitro after nociceptin injection did not differ from that of controls. The findings suggest that nociceptin acts on the hypothalamus to stimulate TRH and TSH secretion.