Treatments, disease affect spermatogonia in boys
Dr Stukenborg noted that the germ cell pool was totally depleted in 5 of the boys with SCD, and the pool was “very low” in the sixth SCD patient.
“This was not seen in patients who had not started treatment or were treated with non-alkylating agents or in the biobank tissues,” Dr Stukenborg said.2
He and his colleagues noted that it is possible for germ cells to recover to normal levels after treatment that is highly toxic to the testes, but high doses of alkylating agents and radiotherapy to the testicles are strongly associated with permanent or long-term infertility.
“The first group of boys who received bone marrow transplants are now reaching their thirties,” said study author Kirsi Jahnukainen, MD, PhD, of Helsinki University Central Hospital in Finland.
“Recent data suggest they may have a high chance of their sperm production recovering, even if they received high-dose alkylating therapies, so long as they had no testicular irradiation.”
Impact of disease
The researchers also found evidence to suggest that, for some boys, their disease may have affected spermatogonial cell counts before any treatment began.
Five patients with non-malignant disease who had not been exposed to chemotherapy (3 with thalassemia major, 1 with Fanconi anemia, and 1 with primary immunodeficiency) had a significantly lower mean S/T value (0.4 ± 0.5) than controls (P=0.006).
“Among patients who had not been treated previously with chemotherapy, there were several boys with a low number of germ cells for their age,” Dr Jahnukainen said.
“This suggests that some non-malignant diseases that require bone marrow transplants may affect the fertility of young boys even before exposure to therapy that is toxic for the testes.”
The researchers noted that a limitation of this study was that biobank samples had no detailed information regarding previous medical treatments and testicular volumes.
1. Testicular tissue is taken from patients under general anesthesia. The surgeon removes approximately 20% of the tissue from the testicular capsule in one of the testicles. For this study, a third of the tissue was taken to the Karolinska Institutet for analysis.
2. A recent meta-analysis showed that normal testicular tissue samples of newborns contain approximately 2.5 germ cells per tubular cross-section. This number decreases to approximately 1.2 within the first 3 years of age, followed by an increase up to 2.6 germ cells per tubular cross-section at 6 to 7 years, reaching a plateau until the age of 11. At the onset of puberty, an increase of up to 7 spermatogonia per tubular cross-section could be observed.
