Fluorescence-Based Ratiometric Analysis of Sperm Centrioles (FRAC) Finds Patient Age and Sperm Morphology Are Associated with Centriole Quality
Article (Faculty180)
A large proportion of infertility and miscarriage causes are unknown. One potential cause is a defective sperm centriole, a subcellular structure essential for sperm motility and embryonic development. Yet, the extent to which centriolar maladies contribute to male infertility is unknown due to the lack of a convenient way to assess centriole quality.
We developed a robust, location-based, ratiometric assay to overcome this roadblock, the Fluorescence-based Ratiometric Assessment of Centrioles (FRAC). We performed a case series study with semen samples from 33 patients, separated using differential
gradient centrifugation into higher-grade (pellet) and lower-grade (interface) sperm fractions. Using a reference population of higher-grade sperm from infertile men with
morphologically standard sperm, we found that 79% of higher-grade sperm of infertile
men with substandard sperm morphology have suboptimal centrioles (P = 0.0005).
Moreover, tubulin labeling of the sperm distal centriole correlates negatively with age
(P = 0.004, R = 0.66). These findings suggest that FRAC is a sensitive method and
that patient age and sperm morphology are associated with centriole quality.