Novel markers for proof of sperm quality – easy and standardized detection of male infertility problems

Challenge

An estimated 48.5 million couples worldwide are affected by infertility. 40% of cases are linked to men. An important factor of male infertility is an insufficient quality of sperms due to abnormal shape and/or motility.

The gold standard for the analysis of sperm quality is the spermiogram (assessment of concentration, motility and shape according to WHO rules). However, this method is subject to variation and has to be repeated at least twice every 12 weeks. Spermiogram can only be performed with ejaculates not older than one hour and need to be performed by certified laboratories and accordingly educated persons. Therefore, there is a strong need for more reliable and standardized diagnostic method that is easy to be performed. The labeling of sperms with Vim3 seems to be a reliable marker for the detection of sperms with fertilizing capacity, whereas the detection of Mxi-2 is an indicator for the sperms without fertilizing capacity.

Technology

Vimentin 3 (Vim3) and Mxi2 are reliable markers for the differentiation of sperm quality. Vim3 works as a counter marker to Mxi2 and can be used in synopsis with Mxi2. Results show

a) In normozoospermia Vim3 is highly expressed and located in the neck and tail domain of functional sperms. Mxi2 is expressed in exactly the opposite way: It is significantly downregulated in sperms with fertilizing function.

b) In oligoasthenoteratozoospermia (OAT) Vim3 is significantly downregulated; Vim3 is predominantly expressed in the head and neck domain of sperms but with decreased signal intensity. Mxi2 is expressed in exactly the opposite way: Mxi2 is upregulated and predominantly located in head and parts of the tail/neck region.

Vim3 and Mxi2 show reproducible results for the differentiation between normozoospermia and OAT, even in fresh as well as in frozen samples. Vim3 and Mxi2 staining overcomes variations of manually assessed sperm morphology and motility in spermiograms. The inventive test would allow an answer on the quality and thus the fertilization capacity.

planned procedure: Urologist gives patient a test kit, patient carries it out at home without stress and discusses the results afterwards with the doctor with subsequent therapy and recommendation.

Vim3 is associated with the presence of high numbers of mitochondria. In sperms with fertilization capacity, mitochondria are only present in the neck region; unfunctional sperms from patients with OAT syndrome show a signal for Mxi2 whereas sperms with fertilizing capacity do not. Mxi2 is the truncated variant of MAPK p38. MAPK p38 was already mentioned in the literature as being overexpressed in sperms with lower quality.

Commercial Opportunity

In-licensing and co-development

Development Status

To date, 150 ejaculates with OAT and normozoospermia have been examined (staining-microscopic examination, determination of the content of both proteins). A validation on about 400 samples is planned. Both antibodies show significant results in the different pathological ejaculates analyzed via FACS (60 ejaculates). Other abnormal pathological ejaculates were as well examined (n=50). A lateral flow test for Vim3 is developed which allows the quick analysis of ejaculates prio to spermiograms. In parallel, an evaluation software is to be developed with a company.

Patent Situation

For the Vim3 marker a EP and US application are pending. For the Mxi2 marker a PCT application is pending

Further Reading

Funke, T. et al. (2019) Vimentin 3 Allows Differentiation between Normozoospermia and Oligoasthenoteratozoospermia. Disease Markers 2019, doi.org/10.1155/2019/9803498

Disease Markers 2019, doi.org/10.1155/2019/9803498