Nerve regeneration: might this be the only solution for functional problems of the urinary tract?

Regeneration and functional recovery of intrapelvic nerves removed during extensive surgery by a new artificial nerve conduit: a breakthrough to radical operation for locally advanced and recurrent rectal cancers

PURPOSE

In the current strategy against locally advanced and recurrent rectal cancers possibly involving intrapelvic nerves, there has been a serious dilemma between extensive surgery and limited surgery. The former can attain high tumor curability by sacrificing the nerve functions while the latter prioritizes the patient quality of life by preserving the nerve functions but with a compromised curability. Here we present a new surgical strategy for locally advanced and recurrent rectal cancers, which realize both high tumor curability and good quality of life.

METHODS

A new artificial nerve conduit (polyglycolic acid collagen tube) developed by in site tissue engineering technology was applied to recovery the disturbed functions after removing the nerves from 11 patients undergoing extensive surgery for intrapelvic advanced or recurrent colorectal cancers. The reconstructed nerves included eight autonomic nerves which are essential for the genitourinary function and three somatic nerves which control the sensation and mobility of the legs.

RESULTS

Out of ten cases followed up more than 2 years and evaluated fully, eight including two report cases showed a functional recovery of the disturbed autonomic and somatic nerves clinically. The nerve function started to recover from 3 to 6 months after the operation and continued to improve with times. No specific complications associated with the nerve repair have been noted.

CONCLUSIONS

The new strategy utilizing the nerve conduit can be a breakthrough in radical operations for locally advanced and recurrent rectal cancers to resolve the problems between tumor curability and the patient quality of life.

Long-term urinary dysfunction after mesorectal excision: A prospective study with intraoperative electrophysiological confirmation of nerve preservation

BACKGROUND

Bladder dysfunctions are well-recognized complications after nerve-sparing mesorectal excision for rectal cancer. This study sought to symptomatically analyze the extent of recovery from major and minor urinary symptoms in patients with signs of bladder denervation.

METHODS

Sixty-two patients with mesorectal excision for rectal cancer were investigated prospectively. Pelvic autonomic nerve preservation (PANP) was assessed macroscopically and with the aid of intraoperative electrical stimulation of pelvic autonomic nerves (INS). Bladder function was evaluated with the International Prostate Symptom Score (IPSS) and the Quality of life index (Qol). Median follow-up was 20 months (range 3-40 months).

RESULTS

Forty-six patients with INS-confirmed preservation of parasympathetic nerves remained unchanged in early and long-term urinary function (IPSS: median 1; range 0-24 and Qol 0; range 0-5). In 15 patients without confirmation of PANP (unilaterally or bilaterally) on INS, voiding function was significantly more impaired postoperatively (IPSS: median 10; range 0-25 and Qol 3; range 0-6) and at long-term follow-up (IPSS: median 9; range 0-25 and Qol 3; range 0-6) (p<0.001). Voiding function was improved in 4 of 10 patients with major and minor symptoms. In 5 of 6 patients with long-term bladder dysfunction INS assessed parasympathetic nerve damage unilaterally (3/5) and bilaterally (2/5).

CONCLUSION

Long-term voiding disturbance after mesorectal excision was found to be a serious complication. INS while monitoring intravesical pressure is a valuable aid in predicting long-term bladder function after TME. The device may serve a secondary preventive function in enabling the initiation of early urologic therapy.

[Regenerative medicine in andrology: tissue engineering and gene therapy as potential treatment options for penile deformations and erectile dysfunction]

Tissue engineering and gene therapy are currently investigated in animal studies for reconstructing penile tissue or treating erectile dysfunction. This review aims to ecamine these experimental efforts from the last years and tries to give a brief introduction to the basic methodology of these new techniques from the field of regenerative medicine.

Neurologic recovery and improved detrusor contractility using muscle-derived cells in rat model of unilateral pelvic nerve transection

OBJECTIVES

To create a model of peripheral neuropathy and explore the potential of using muscle-derived cells (MDCs) to facilitate the regeneration of autonomic nerves and improve bladder function. Damage to the peripheral nerves that innervate the bladder from radical pelvic surgery is refractory to the currently available treatments.

METHODS

Rat MDCs were isolated from the gastrocnemius muscle using the preplate technique. The unilateral pelvic nerve was cut in female Sprague-Dawley rats. Three experimental groups were included: control (n = 5); unilateral pelvic nerve transected with sham injection (n = 5); and unilateral pelvic nerve transected with injection of MDC (3 x 10(5) cells/site; n = 5). Two weeks after injection, the intravesical pressures were measured during electrical stimulation of the proximal transected preganglionic nerve. The contralateral major pelvic ganglion was excised to ensure that any observed bladder activity was due exclusively to inputs on the unilateral side. The rats were killed, the experimental side major pelvic ganglion was removed, and enkephalin immunoreactivity was counted.

RESULTS

After unilateral pelvic nerve transection, no change occurred in bladder weight or capacity or postvoid residual urine volume. The maximal intravesical pressures for the control, sham, and MDC groups, after the contralateral pelvis had been cut, was 31.7 +/- 10.3, 9.6 +/- 4.5, and 15.2 +/- 7.7 cm H2O, respectively (P <0.05). After transecting the preganglionic pelvic nerve, the intensity of pericellular enkephalin immunoreactivity varicosities was significantly decreased in the sham group but unchanged in the MDC group compared with the control group.

CONCLUSIONS

MDCs can promote peripheral autonomic nerve regeneration. The morphologic changes correlated with the functional neurologic recovery effect of MDCs. The underlying neurologic recovery mechanisms of MDCs need to be exploited.

Stem cell transplantation and other novel techniques for promoting recovery from spinal cord injury

A number of potential approaches aim to optimize functional recovery after spinal cord injury. They include minimizing the progression of secondary injury, manipulating the neuroinhibitory environment of the spinal cord, replacing lost tissue with transplanted cells or peripheral nerve grafts, remyelinating denuded axons, and maximizing the intrinsic regenerative potential of endogenous progenitor cells. We review the application of stem cell transplantation to the spinal cord, emphasizing the use of embryonic stem cells for remyelinating damaged axons. We speculate that harnessing the potential of endogenously born stem cells already present in the spinal cord represents an important therapeutic target. We also discuss the potential application of peripheral nervous system reconstruction to recovery from spinal cord injury. The principles of peripheral nerve regeneration and concepts of nerve grafting are reviewed. Particular attention is given to peripheral nerve allotransplantation for repairing extensively injured tissue when autologous donor nerve material is scarce. The potential role of nerve transfers for reconstructing the injured spinal cord, particularly the cauda equina and lumbosacral plexus, are also described.