Jeffrey T. Jensen

Despite the widespread availability of contraceptives, many sexually active couples use no method of birth control, while others use methods inconsistently or incorrectly. This contributes to an unacceptably high rate of unintended pregnancies, unwanted births and abortions. In addition, the most effective current methods of contraception involve steroid hormones and may cause various side effects in certain individuals. Misperceptions regarding those side effects, particularly the risk of cancer, often interfere with use of the contraceptives. Research leading to non-hormone-related methods of birth control may reduce the number of unintended pregnancies and improve public health.

Jeffrey Jensen's clinical experience in family planning inspires his dedication to the development of new methods of contraception. He and his staff focus on translational research designed to bring the advances of the lab into clinical practice.

Building on research in rodents, Jensen's group has documented that the phosphodiesterase (PDE) 3 inhibitor, ORG 9935, can prevent maturation of the oocyte both in the culture dish and during stimulated ovarian cycles, and can act as a contraceptive in breeding groups of macaques. It has the advantage, however, of not affecting menstrual cycles. Future experiments in monkeys are needed to determine if the approach is feasible in women. New studies with novel inhibitors of oocyte maturation are in progress as part of the recently funded NICHD Contraceptive Research Development Center at ONPRC. Dr Jensen is a co-Principal Investigator of this grant that is investigating the biology of several highly specific and novel contraceptive strategies, and testing promising applications in the breeding groups.

Globally, surgical sterilization is the most common and effective method of birth control. Because access to this important method is limited by its high cost, the scarcity of providers, and certain surgical risks, particularly in lesser-developed nations, there is a need for a non-surgical method of sterilization. A number of chemical agents have been evaluated for that role, but only quinacrine has been tested in humans. The World Health Organization has placed a moratorium on funding further clinical quinacrine studies, pending more animal studies of its long-term safety.

In collaboration with colleagues in Europe, Jensen has investigated Polidocanol, a synthetic, long-chain, fatty alcohol used as a sclerosing agent, for its potential in non-surgical sterilization. In contrast to promising results obtained in rodents, transcervical Polidocanol has failed to result in tubal blockade in rhesus monkeys. These experiments underscore the importance of using the monkey model to test potential chemical sterilization agents prior to their use in women.

Biography

Jeffrey T. Jensen is an Affiliate Senior Scientist in the Division of Reproductive Sciences, Leon Speroff Professor of Obstetrics & Gynecology in the School of Medicine, OHSU, and Director of the Women's Health Research Unit of the Center for Women's Health at OHSU. He completed medical school at Emory University (1984), an internship at Santa Clara Valley Medical Center (1985), and residency training in Obstetrics and Gynecology at OHSU (1988) before entering active duty military service in the United States Navy. He became a member of the OHSU faculty in 1992. Jensen received a Master of Public Health degree from the University of Washington in 1997, and he joined the ONPRC staff in 1999 as a Women's Reproductive Health Research Fellow.

Key Publications

Jensen JT, Zelinski MB, Stanley JE, Fanton JW, Stouffer RL. The phosphodiesterase 3 inhibitor ORG 9935 inhibits oocyte maturation in the naturally selected dominant follicle in rhesus macaques. Contraception 2008;77(4):303-7.

Jensen JT, Stanley JE, Zelinski MB, Stouffer RL, Jacob D and Fanton J: Use of controlled ovulation of the dominant follicle to assess oocyte maturation during natural menstrual cycles in rhesus macaques. Fertil Steril, 2007;87:1477-9.

Jensen JT, Zelinski-Wooten MB, Schwinof KM, Vance J, Stouffer RL. The phosphodiesterase 3 inhibitor ORG 9935 inhibits oocyte maturation during gonadotropin stimulated ovarian cycles in rhesus macaques. Contraception 2005;71(1):68-73

Jensen, J.T.,M.I. Rodriguez, J. Liechtenstein-Zábrák, and S. Zalanyi. 2004. Transcervical polidocanol as a nonsurgical method of female sterilization: A pilot study. Contraception70(2): 111-115.

Jensen, J.T., K.M. Schwinof, M.B Zelinski-Wooten, M. Conti, L.V. DePaolo, and R.L. Stouffer. 2002. Phosphodiesterase 3 inhibitors selectively block the spontaneous resumption of meiosis by macaque oocytes in vitro. Hum. Reprod.17(8): 2079-2084.

To see a full listing of Dr. Jensen's publications click here