Q from U: How detrimental are vacuoles in sperm?

September 15, 2013Carole No Comments »

Another blog post idea came in from a patient recently.

Question: I would like to see a topic on what happens for those with vacuoles on the sperm.
1) Can sperm that looks normal but has vacuoles actually penetrate the egg? Or do they lack the ability to do so?
2) What does it look like under high magnification? How do they select the right sperm for ICSI?

Although you can see  vacuoles at the traditional  high magnifications (400X) used for routine sperm morphology analysis and ICSI selection, these vacuoles are much easier to see at the extremely high magnification (8000X)  using a procedure called IMSI. Here’s a YouTube video that shows the difference in magnification between ICSI and IMSI. This video answers the second question by showing how sperm are selected. Basically, IMSI is used to make it easier to see fine details on the sperm and avoid selection sperm that have head vacuoles or other abnormalities. A review of multiple research studies support the idea that head vacuoles are considered to indicate defects in the chromatin or DNA packaging of the sperm.

Research exists to support the idea that IMSI selection  is beneficial. One example is this study which looked at two groups of patients who had sperm injection, one using the original ICSI selection technique and the other group had sperm selection at higher magnification. They found that embryos could be produced with either method but when you looked at the pregnancy rate and abortion rate, there were better outcomes for embryos created using IMSI selected sperm.  So the answer to the first question is that yes, sperm with vacuoles can penetrate the egg and create embryos. But it seems that these embryos might be at a disadvantage because they might have received poorly packaged DNA, which had negative implications for the longer term survival of the embryos and healthy pregnancy outcomes. There are other on-going clinical trials to further evaluate the benefit of IMSI.

Pictures of normal sperm heads (no vacuoles in Fig A) and vacuoles in sperm heads (Fig B).

http://www.rbej.com/content/figures/1477-7827-8-56-1-l.jpg

Morphological sperm forms. A: Normal spermatozoa observed at high magnification (≥8400×); B: Spermatozoa with large nuclear vacuoles observed at high magnification (≥8400×).

Oliveira et al. Reproductive Biology and Endocrinology 2010 8:56   doi:10.1186/1477-7827-8-56

 

 

 

© 2013, Carole. All rights reserved.

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