Posts Tagged ‘pathology’

Rare stem cells hold potential for infertility treatments

Researchers studying infertility in mouse models found that, unlike similar types of cells that develop into sperm, the stem cells that express PAX7 can survive treatment with toxic drugs and radiation. If the findings hold true in people, they eventually could lead to new strategies to restore or protect fertility in men undergoing cancer treatment.

“Unfortunately, many cancer treatments negatively impact fertility, and men who receive such treatments are at high risk of losing their fertility. This is of great concern among cancer patients,” said Dr. Diego H. Castrillon, Associate Professor of Pathology and Director of Investigative Pathology. “The PAX7 stem cells we identified proved highly resistant to cancer treatments, suggesting that they may be the cells responsible for the recovery of fertility following such treatments.”

Infertility, which the Centers for Disease Control estimates affects as many as 4.7 million men in the United States, is a key complication of cancer treatments, such as chemotherapy and radiation therapy.

The new findings, presented in the Journal of Clinical Investigation, provide valuable insight into the process of sperm development. Known as spermatogenesis, sperm development is driven by a population of “immature” stem cells called progenitors in the testes. These cells gradually “mature” into fully differentiated sperm cells. Dr. Castrillon and his team tracked progenitor cells that express the protein PAX7 in mouse testes, and found that these cells gradually give rise to mature sperm.

“We have long known that male fertility is driven by rare stem cells within the testes, but the precise identity of these stem cells has been disputed,” said Dr. Castrillon, who holds the John H. Childers, M.D. Professorship in Pathology. “Our findings suggest that these rare PAX7 cells are the key cells within the testes that are ultimately responsible for male fertility.”

Importantly, even after exposure to toxic chemotherapy or radiation treatments, the PAX7-expressing cells continued to divide and thus could contribute to restoring sperm development.

source : http://www.sciencedaily.com/releases/2014/09/140904153805.htm

Clearing cells to prevent cervical cancer

The findings come from a study that looked at squamocolumnar junction cells, or SCJ cells. These cells reside in the cervical canal and have been implicated as the origins of cervical cancer. A research team co-led by Christopher Crum, MD, director, Brigham and Women’s Hospital (BWH) Women’s and Perinatal Pathology, demonstrated that removal of SCJ cells resulted in a markedly lower risk of cervical intraepithelial neoplasia — a non-cancerous, abnormal growth of cells on the surface of the cervix that may progress to cervical cancer.

One hundred and thirty-one women with cervical intraepithelial neoplasia were treated with a loop electrosurgical excision procedure to remove the SCJ cells. During the follow-up period (of up to four years), 16 recurrences were identified. Four were identified at the first follow-up visit, and determined to be residual disease, meaning they were not removed in the initial procedure. Twelve manifested after the first postoperative visit and all were in the ectocervix or in mature metaplastic epithelium. All of the 12 delayed recurrences were cervical intraepithelial neoplasias and did not have SCJ cells.

“We have always suspected that most recurrences following apparently successful therapy do not develop in the same location as the original precancer, which was at the squamocolumnar junction,” said Crum. “Moreover, studies in the literature have shown that the risk of a significant precancer following successful removal is quite low. Our study is in sync with these observations and suggests that removing SCJ cells might have a significant impact in reducing the risk of cervical cancer.”

Crum emphasizes that eliminating SCJ cells does not prevent cervical intraepithelial neoplasias nor does it prevent human papilloma virus (HPV) infection — which can lead to cervical cancer. But what is significant about the findings, according to the researchers, is that removal of SCJ cells seems to alter recurrence patterns, presumably by removing the population that is most vulnerable to development of the more dangerous precancers.

“This is a concept that is in great need of a controlled clinical trial aimed at prevention rather than treatment,” said Crum. “It would give us important insights into whether preemptive removal of the SCJ region would have the desired effect.”

An accompanying editorial, by Silvia Franceschi, MD, International Agency for Research on Cancer, suggests continuation of the work by “careful evaluation of the impact of prophylactic ablation in the framework of large screening programmes.”

source : http://www.sciencedaily.com/releases/2014/07/140725131558.htm