Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Hollow or tubular part or organ
Reexamination Certificate
2001-12-13
2003-09-16
Willse, David H. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Hollow or tubular part or organ
C623S023670
Reexamination Certificate
active
06620203
ABSTRACT:
FIELD OF THE INVENTION
The present invention is generally directed to a tissue engineered (TE) testicular prosthesis having both cosmetic and therapeutic uses.
BACKGROUND OF THE INVENTION
Testicular dysfunction, characterized by either an absence of androgenic production, an absence of the testes, or both, has great medical and psychological consequences on the afflicted male population ranging from infertility and cancer to psychiatric disturbances. Causes of testicular dysfunction include chromosomal abnormalities, testicular torsion (which may be a result of inadequate connective tissue within the scrotum or trauma to the scrotum, after strenuous exercise or without an obvious cause; the incidence is higher during infancy and with the onset of adolescence) direct trauma to the testicles, diseases that affect the testicle (such as mumps orchitis and testicular cancer), and a variety of drugs. Increased risk is associated with activities that may cause constant, low level trauma to the scrotum (such as riding a motorcycle) or frequent administration of a drug known to affect testicular function (such as heavy marijuana use or taking some prescription medications). Thus, testicular dysfunction can result at the time of fetal development, adolescence and during the adult years.
During fetal development, the fetal testes are formed within the abdominal cavity in the region where the kidneys are normally located in adults. They descend into their normal scrotal position shortly before birth. The prevalence of undescended testes (cryptorchidism) is 3.4% in full-term infants and as high as 30% in premature infants. The testes often descend after birth, and the prevalence of cryptorchidism by one year of age is down to 1%. Current practice is to surgically correct undescended testes at around age one year. The main reason for bringing the testes down early is to preserve future fertility. Testicular atrophy may be present due to a primary abnormality of the testis or due to damage incurred during surgery. A testicular prosthesis could be inserted for cosmetic reasons, but the undescended testicle may have to be removed to achieve the desired “normal” result. This undescended testes may be producing hormones and be worth sparing. However, the risks of inserting a testicular prosthesis are minimal and consist of infection (around 2%) and bruising. Physicians frequently recommend that a testicular prosthesis be placed early in life to prevent shrinkage of the scrotum which can occur when the sac is empty, and allow for normal psychological development through the patient's early years.
In addition, there is an association between cryptorchidism and testicular cancer. Approximately 10% of testicular tumors arise from an undescended testis, and the risk of malignancy in an undescended testis is thought to be 35-fold higher than for a normal descended testis. The best way to detect testicular cancer is by palpation. Thus, another reason for surgically correcting cryptorchidism is to allow the patient to easily perform monthly self-examination. Yet despite this increased risk, the annual risk of malignancy is estimated to be only one in 2,550 cases. Moreover, the risk of death from removal of the testis is higher than the risk of testicular cancer in patients over 32 years of age.
To date, testicular prosthesis have been of solid material or have been filled with a soft silicone elastomer or a silicone gel. See “The Why and How of Synthetic Replacement Testicles” by Joseph Ortenberg. M.D. and Robert G. Kupper, M.D. in Contemporary Urology. October 1991. pp 23-32. Moreover, no testicular implants have been sold in the U.S. since 1995, when the FDA called for a pre-market approval application on these devices in fear of harmful effect of silicone. As a result, Silicone Gel implants are not available in the U.S., and the American Urological Association have advised against using these products. A Silicone Elastomer prosthesis may be available, and is endorsed for use by the American Urological Association. Hence, alternatives to testicular implants are very limited, leaving patients with few treatment options.
Recently, Mentor Corporation of Santa Barbara, Calif. developed a saline-filled implant which is currently awaiting the FDA approval. The Mentor testicular prosthesis approximates the weight, shape, and feel of a normal testicle. The prosthesis is available in four sizes, extra small, small, medium, and large. The implant consists of a molded silicone-elastomer shell approximately 0.035 inches thick, with a self-sealing injection site located on one end of the prosthesis. The injection site allows the surgeon to fill the implant with sterile, pyrogen-free Sodium Chloride USP solution. On the end opposite of the fill site is a silicone elastomer tab for suturing the prosthesis in place. See U.S. Pat. Nos. 6,060,639 and 5,653,757.
The prosthetic testicles that are available today have a realistic appearance but may feel foreign (hard) and cause discomfort. It is not uncommon for patients to remove the prosthesis several years later due to pain and discomfort. Because artificial testicles do not move as natural testicle do, they sometimes become fixed in peculiar positions thereby causing the scrotum to hang abnormally. Moreover, with the normal developmental growth, corresponding larger testicle sizes must be surgically replaced. With the available prosthetic options, it is often recommended to young patients to attenuate prosthetic placement as long as possible in order to reduce the number of procedures required to maintain the appropriate testicle size. This of course does not address the emotional issues associated with the artificial testicle and numerous replacement surgeries. Additionally, male patients with an absence of testes (anorchia) commonly require testicular prosthesis placement and hormone replacement treatment. Unfortunately, the currently available testicular prosthesis have no capabilities to produce and supply androgenic substances, and the several types of testosterone compounds and various modes of hormone deliver, that are currently used clinically, however, have pharmacokinetic properties that are not ideal.
The testes of male mammals, including humans, is the source of circulating androgens that are responsible for the maintenance of the secondary sexual characteristics in the male. In most species, the testes is divided into two separate compartments: the seminiferous tubules that contain the Sertoli cells, the peritubular cells and the germ cells; and the interstitial compartment that contains the Leydig cells, macrophages, lymphocytes, granulocytes and the cells composing the blood, nerve and lymphatic structures. Leydig cells are interspersed between the various coils of the seminiferous tubules, and are responsible for the production of androgens or male sex hormones.
The Leydig cells, located in the interstitial compartment and comprising approximately 2-3% of the total testicular cell number in most species, are the only testicular cells capable of the first two steps in steroidogenesis; i) the conversion of cholesterol, the substrate for all steroid hormones, to pregnenolone: and ii) conversion of pregnenolone to progesterone. Therefore, the interstitial compartment in general, and the Leydig cells in particular synthesize virtually all of the steroids produced in the testis with testosterone being the major steroid biosynthesized.
The major stimulus for the biosynthesis of testosterone in the Leydig cell is the gonadotrophic hormone, luteinizing hormone (LH). LH is secreted from specific cells located in the anterior pituitary and it interacts with specific receptors on the surface of the Leydig cell and initiates the signal for testosterone production. Cellular events occur rapidly in response to the trophic hormone stimulation of Leydig cells, and result in the synthesis and secretion of testosterone.
Patients with testicular dysfunction require androgen replacement for somatic development. “Androgen” refers to a family of male sex hormones which
Nixon & Peabody LLP
Phan Hieu
Willse David H.
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