Google +

Dr. Brackett

Research Interests







Contact Information:


The Miami Project
to Cure Paralysis


1095 NW 14th Terrace


Locator Code R-48


Miami, Florida 33136



Tel:  (305) 243-8181
Fax: (305) 243-3913



Home > Our Research Faculty > Nancy L. Brackett, Ph.D.






Research Professor, Departments of Urology and Neurological Surgery



Male Fertility following Spinal Cord Injury


Research Interests

Nancy L. Brackett, Ph.D., HCLD


The research in my laboratory is focused on understanding and improving the impairments to male fertility which occur following spinal cord injury (SCI). Following SCI, most men, but not women, experience impaired fertility. Specifically, most men with SCI are anejaculatory, and some experience erectile dysfunction. Although their semen may be obtained by medically-assisted ejaculation procedures, in most cases, semen quality is impaired, specifically, sperm motility and viability are abnormally low, although sperm numbers tend to be normal.


Our research is focused on determining the cause of impaired semen quality in men with SCI. Our studies have shown that factors secondary to SCI are not responsible for impaired semen quality in men with SCI. For example, the condition is not due to scrotal thermoregulatory dysfunction, the method or frequency of ejaculation, the number of ensuing years post-injury, or hormonal alterations. Our recent evidence indicates that the problem is related to the seminal plasma. For example, seminal plasma of men with SCI inhibits sperm motility of able-bodied men. In addition, sperm motility is much higher in men with SCI before the sperm mix with seminal plasma. Substances within the seminal plasma are abnormal in men with SCI, including elevated reactive oxygen species, decreased prostate specific antigen (a marker of prostate function) and decreased fructose (a marker of seminal vesicle function). The semen of men with SCI contains an abnormally high number of non-spermatozoon cells, most of which are leukocytes. Our current research is investigating inflammatory factors, including semen cytokine levels, as contributors to the problem. Our ultimate goal is to develop therapies to normalize semen quality in men with SCI, so that chances of biological fatherhood are increased.


In addition to our investigation of the seminal plasma, we are studying methods to improve semen retrieval and semen processing for assisted conception procedures. Recent improvements treating male infertility in the general population have led to a problem for men with SCI. Often, their ejaculates are not examined as a source of sperm for assisted reproductive technology (ART). Instead, sperm are retrieved surgically from their testes or epididymes as a first line treatment for anejaculation. This development has resulted in many centers performing expensive and invasive ART to overcome the low sperm numbers typically obtained with surgical sperm retrieval. Our research is focused on optimizing non-surgical methods of obtaining sperm from men with SCI. By maximizing the total motile sperm available for ART, couples have a wider range of options for pursuing assisted conception. Our research is leading the field by establishing standards of care for treatment of infertility in men with SCI.





Copyright 2014 University of Miami. All rights reserved.