Discusion
Recent years, more and more stdudies about MMAF had been reported, and
normaI fants were delivered following ICSI with ejaculated
sperm[6,8,10-13,21,23,26,28,30,31].To our knowledge , the present
case is the first report of Successful birth after injection of
vitrified oocyte by immotile testicular spermatozo with totally MMAF.
This report shows that even in case of MMAF patient,vitrified oocytes
can be successfully fertilizated by ICSI ,and produce healthy
offspring.Thus,Vitrification may serve as a useful tool in the
preservation of oocytes for MMAF couples .
Oocyte cryopreservation has become an important part of infertility
treatment for various reasons.In our case,vitrification of a part of
oocyte cohort was proposed to save oocytes for a potential subsequent
ICSI cycle in case of no embryos available in the first cycle. Oocyte
survival at the MII stage after warming, for this case report, was 100%
(12/12 oocytes),similar to the post-warming survival rates of 96.4%
with 86.2% fertilization rate in 2020 from Deepa Talreja[10]. In R
Azambuja’s report,it is 63% and 80% respectively[18]. While the
fertilization rate in this report was 75% (9/12 surviving oocytes
fertilized). This difference might be related to the different sperm
origin, seriously impaired sperm motility of MMAF ;
According to the previos study, majority of the succesful MMAF cases are
from the ejaculated sperm[1,3,5-8,14,15,22,23,25,27]. It is uncommon
for MMAF patients that both the flagellar of the ejaculated sperm and
testicular spermatoza are 100% abnormal and totally immotile.In Yang’s
report, testicular spermatozoa were obtained by needle aspiration,which
were also showed 100% immotile,but with a small portion of nomal
flagella. And the sperm flagellar phenotype was in accordance with
MMAF,showing absent 20.0%, short38.5%, coiled 30.5%, irregular 5.5%,
and bent 5.5%,respectively[21]. Robert l showed a PCD patient that
all testicular sperm were immotile,and the majority were structurally
abnormal,being decapitated and with short thickened tails[19].
Similar to the above reports,both of the ejaculated and testicular
spermatozoa were totally immotile and 100% abnomal flagella in our
case(Figure1A). Different from them,Under light microscopy, 84% of the
sperm flagellar phenotype were showing curled or bent back on itself at
the end piece of the flagellar, but with normal head and middle piece
percentage(Table1). To our knowledge, the case is the first report of
MMAF that all the the morphology of the flagellar are abnormal,and
majority of the end piece of the flagellar were cureled or bent.
The percentage of each abnormal sperm flagellar phenotypes was different
in different MMAF patients.This difference might be related to the
different disease-causing genes. Recent years, more and more new genes
are reported to be associated with MMAF, including the latest DNAH8,
DNAH17, CFAP61, QRICH2 and CFAP74[6,23,26,30,31]. These uncovered
genes always lead to disrupted ultrastructural defects of the axoneme,
which is the core structure of the sperm flagellar, several axonemal
dyneins, radial spokes, nexin links and many other components. Any
defects in these structures would result in abnormal sperm flagellar,
showing a mosaic of morphological abnormalities, and further lead to
severe asthenozoospermia or 100% sperm immotility.
The immotile spermatozoa in MMAF patients showed a viability of
9%–80%,and fertilization rate of 38.9%-75%[7,25 ]. These
results are quite similar to those observed here. In the present case,
with a Viability of 39%,the first ICSI cycle attempt with ejaculated
sperm resulted in a 60% fertilization rate. While in the second cycle
with fresh testicular spermatozoa,it was a better 75% fertilization
rate.Yang’s report showed a 45.5% fertilization rate,when testicular
spermatozoa from a MMAF patient were injected into the oocytes[21].
Twelve of 18 oocytes were fertilized in another MMAF-like PCD patient
after testicular sperm extraction and intracytoplasmic sperm
injection[19].Our results further demonstrated that testicular sperm
with MMAF are capable of establishing a normal pregnancy,regardless of
also being immotile and totally abnormal . Moreover, maybe immotile
testicular sperm is better than immotile ejaculated sperm and has been
recommended for use rather than completely immotile ejaculated sperm in
MMAF patients.
Addationally,This difference of fertilization rate might be related to
the selection of viable sperms. The hypo-osmotic swelling test to
evaluate the vitality of the spermatozoa prior to ICSI was not possible
because of the totally abnormal end piece of the flagella. All of the
spermatozoa in the papient exhibit curlings of the flagellum that
resemble HOS-positive spermatozoa. This especially lilmited the
efficency of the HOS test ,and the result would be inaccurate. In our
case, morphologically and physical characteristics (tail flaccidity)
were used to select sperm,accurately,the curled flagellar with normal
head(Figure1B). A similar fertilization rate (67%) was achieved.This
demonstrates that a high fertilization rate can be obtained even if HOS
is not used for MMAF patients.
Interestingly, it was reported that the success rates of ICSI may be
correlated to the type of ultrastructural flagellar defect carried by
the patients. Mitchelletal reported lower implantation(8%) and clinical
pregnancy rates(15%) in patients without axonemal centralpair[15] .
Unfortunately,In the patient reported here,TEM was not done on the
sample , so the ultrastructure of the spermatozoa is unknown.
The is no doubt that the finding genes provided strong genetic evidence
for MMAF[17,20,22,26-31]. Thus, genetic counseling is highly
significant in helping evaluate and avoid the risk of transmission of
genetic defects by ICSI in these patients. In the present report, the
chances of genetic transmission were lessened by the fact that the
new-born was a girl . However, the possibility that this girl may be a
healthy carrier of the described variant of the immotile cilia syndrome
should be discussed during genetic counseling . We are sure that genetic
counseling and careful analysis using electron microscopy will make the
course of MMAF treatment better .
In conclusion, we firstly reported a sucessful delivery after injection
of vitrified oocyte with immotile
testicular spermatozo with MMAF. Although more and more new genes were
revealed in recent years,these can only explain 35%-60% of the MMAF
cases[31]. Thus,more work will be done in the field of the genetics
of MMAF. In our following study ,more MMAF patients will be collected to
carrying out whole-exome sequencing and Transmission electron microscopy
assessment.
Acknowledgments: The authors thank Bo Ma for assistance in
preparing this manuscript
Disclosure of Interest: the authors declare no competing
interests.
Ethics approval: This is a case study. The Ethics Committee has
confirmed that no ethical approval is required.
Details of patient’s consent: the patient’s permission to
publication was obtained.
Contribution to authorship: Yuhu Li and Yuqun Huang was
responsible for the literature search . Data interpretation and writing
of initial draf twas by Liuguang Zhang . Manuscript writing and
approval was by Liuguang Zhang.
Funding: the research was supported by no funding