Urologic Prostheses

Tissue-engineered tear secretory system: functional lacrimal gland acinar cells cultured on matrix protein-coated substrata

Dry eye is a general term that refers to a myriad of ophthalmic disorders resulting in the inadequate wetting of the corneal surface by the tear film. Dry eyes are typically treated by the application of artificial tears. However, patients with lacrimal insufficiencies such as Stevens-Johnson syndrome, chemical and thermal injuries, or ocular cicatricial pemphigoid have very limited options because of the short duration and action of lubricating agents. As a therapeutic strategy, we are working to develop a bioengineered tear secretory system for such patients. This article describes the growth and physiological properties of purified rabbit lacrimal gland acinar cells (pLGACs) on several matrix protein-coated polymers such as silicone, collagen I, copolymers of poly-D,L-lactide-co-glycolide (PLGA; 85:15 and 50:50), poly-L-lactic acid (PLLA), and Thermanox plastic cell culture coverslips. Monolayers of acinar cells were established on all of the polymeric substrata. An assay of beta-hexosaminidase activity in the supernatant medium showed significant increases in protein secretion, following stimulation with 100 microM carbachol on matrix protein-coated and uncoated polymers such as silicone, PLGA 85:15, and PLLA. Our study demonstrates that PLLA supported the morphological and physiological properties of purified rabbit lacrimal gland epithelial cells more successfully than the others.

Tissue engineering: current and future approaches to ocular surface reconstruction

Although cells have been cultured outside the body for many years, research has only recently begun to develop complex three-dimensional tissue constructs that will, ideally, mature into fully functional tissues and organs. Tissue engineering is an emerging field in the area of biotechnology that combines the principles and methods of life sciences with those of engineering for the purpose of regenerating, repairing, or replacing diseased tissues. In this review, we describe the recent advances and current development of tissue engineering approaches as related to the ocular surface system, which comprises the three main integrated tissue units: conjunctiva, cornea and lacrimal glands.

Management of impending penile prosthesis erosion with a polytetrafluoroethylene distal wind sock graft

PURPOSE

Erosion of penile prostheses can be calamitous, often leaving patients unable to accommodate further implants. There is a paucity of literature describing impending erosion of penile prosthesis. We report on 5 patients with impending erosion of a penile prosthesis who underwent polytetrafluoroethylene distal wind sock graft placement.

MATERIALS AND METHODS

From 1993 to 1997, 5 patients with a mean age of 49 years and impending penile prosthesis erosion underwent 6 revisions using a polytetrafluoroethylene distal wind sock graft. Two patients underwent simultaneous bilateral grafts while 1 patient underwent separate right and left grafts 3 years apart. Indications for reconstruction included distal migration of the prosthetic cylinders into the glans in 4 patients and impingement of the distal urethra in 2. Of the patients 3 were spinal cord injured, 1 had lumbar radiculopathy and 1 had a history of pelvic irradiation. Inflatable prostheses were implanted in 4 patients, while 1 received a malleable prosthesis.

RESULTS

Patients underwent a mean of 1.5 penile prosthetic revisions (0 to 4) before diagnosis of impending erosion. An interval of 8 to 144 months (mean 66) elapsed from the most recent penile prosthesis insertion until distal wind sock graft placement. Mean operative time was 1 hour 51 minutes (1.3 to 2.5 hours). Mean hospital stay was 6.3 days (3 to 12). At a mean followup of 32 months (0.7 to 5.2 years) all patients had satisfactory and functional erections with no pain or evidence of impending erosion or penile prosthesis infection.

CONCLUSIONS

Erosion of a penile prosthesis can have disastrous consequences. We describe a safe and effective technique for managing impending penile prosthesis erosion using a polytetrafluoroethylene distal wind sock graft.