Introduction
Sertoli cells help in spermatogenesis (a cell differentiation procedure responsible for sperm production). They are typically seen in males in the age group between 20 and 40. Sertoli cells line the seminiferous tubules of the testis in Sertoli cell-only syndrome. The Sertoli cells help nurture the immature sperm and form the blood-testis barrier in males. Follicle-stimulating hormone is responsible for the functioning of the Sertoli cells. Seminiferous tubules are the tubes inside the testicles where sperms develop. On physical examination, the patient often appears normal and does not have problems with sexual activity. However, the individual with Sertoli syndrome will have infertility. Testicular biopsy is the method for diagnosis based on the findings, and treatment is provided. Assisted reproductive technology can be used as an adjunct to infertility. There were cases reported in which Sertoli-only syndrome was associated with Klinefelter syndrome.
What Are the Synonyms of Sertoli Cell-Only Syndrome?
The synonyms are:
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Del Castillo syndrome.
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Germ cell aplasia.
What Are Sertoli Cells?
Sertoli cells are also called nurse cells and help in sperm production (spermatogenesis). They are located in the lining or walls of the seminiferous tubules. They provide nutrition to the developing sperm.
What Is the Etiology of Sertoli Cell-Only Syndrome?
Sertoli cells secrete substances that help in the proper growth and development of spermatogonia. They play an important role in reproductive functions in males. Sertoli cells produce an anti-Mullerian hormone (AMH). The anti-Mullerian hormone helps in the regression of Mullerian ducts in the male fetus. The role of the anti-Mullerian hormone is to prevent the development of female reproductive organs during embryogenesis in the male fetus. Inhibin B is secreted by the Sertoli cells, which help regulate follicle-stimulating hormone secretion in the hypothalamus. Activitin is a hormone that helps in secreting higher levels of follicle-stimulating hormone and provides feedback to the hypothalamus for spermatogenesis.
What Is the Epidemiology of Sertoli Cell-Only Syndrome?
It is estimated that around 5 % to 10 % of men with infertility are affected by Sertoli cell syndrome. The only presentation of Sertoli cell-only syndrome is infertility. The individuals show no abnormalities on physical examination, and their sexual activity is not affected. Sertoli cell-only syndrome has a high predilection in caucasian males and affects the age group of 20 to 40 years old.
Pathophysiology of Sertoli Cell-Only Syndrome:
The diagnosis of Sertoli cell-only syndrome is often made when young individuals visit a physician for infertility treatment. On further evaluation, the individual will have reduced or absent spermatogenesis. Most of the time, the pathology of this syndrome involves this pathogenesis. Failure of migration of gonocytes may result in the congenital absence of germ cells. The Y chromosome has different locations or regions, and Yq11 is one of them. The azoospermia factor region is also called the Yq11 region. In individuals with Sertoli cell-only syndrome, there is a deletion in the Y chromosome at the Yq11 region, mainly at the AZFb/b+c region. This may be one of the causes of the disease. Sertoli cell syndrome is idiopathic and multifactorial. A study conducted by Yang et al. stated that deletions between P4 and P3 may be one of the causes. Deletions are seen in intervals between P5 and P1 and also between P4 and P1. Mutations of Fas, Fasl, and active caspase-3 cause apoptotic elimination and altered maturation. Individuals with Sertoli cell-only syndrome have normal levels of luteinizing hormone (LH) and testosterone. Follicle-stimulating hormone levels increase when there is a low level of inhibin-B.
The pathophysiology can be brought down to :
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Genetic causes.
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It can be idiopathic.
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Toxin exposure decreases spermatogenesis.
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Radiation exposure.
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Viral infection.
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Decreased sperm cell production due to trauma or history of trauma.
What Are the Symptoms of Sertoli Cell-Only Syndrome?
An individual is diagnosed with Sertoli cell syndrome only when looking for infertility treatment. Individuals with Sertoli cell-only syndrome have normal sexual function and ejaculation without any warning signs. Studies have shown that individuals with Sertoli cell syndrome may have small testicles in a few cases. Human phenotype data has given conditions that may be associated with Sertoli cell-only syndrome, such as:
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Metabolic abnormalities.
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Gynecomastia (enlarged male breasts).
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Abnormalities in the chest.
Diagnosis of Sertoli Cell-Only Syndrome:
Semen tests help in determining sperm quality and parameters. The parameters include sperm count, sperm concentration, sperm volume, sperm motility (the ability of the sperm to swim), and sperm morphology (shape and size of the sperm). The doctor may advise further tests if the results show low sperm count and concentration. In the tests conducted to check for azoospermia, there will be zero sperm count in the lab results. Further tests like imaging and blood tests to check for genetic, obstructive, or hormonal causes. If the lab tests show increased levels of follicle-stimulating hormone, low testosterone, and with or without high luteinizing hormone, then Sertoli cell syndrome can be confirmed. Low testosterone levels also indicate Klinefelter's syndrome. A biopsy can also confirm the diagnosis of Sertoli cell-only syndrome. A biopsy report will demonstrate few or no sperm cells inside the seminiferous tubules.
What Is the Differential Diagnosis for Sertoli Cell-Only Syndrome?
The following are the differential diagnosis:
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Leydig cell hyperplasia.
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Klinefelter syndrome.
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End-stage testis failure.
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Azoospermia.
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Hypospermatogenesis.
What Is the Treatment for Sertoli Cell-Only Syndrome?
Treatment options for Sertoli cell-only syndrome are not yet available. In certain cases where the individual has a low sperm count, testicular sperm extraction (TESE) can be considered. Testicular sperm extraction is a procedure where the sperm is removed from the individual's testis. With the help of intra cytoplasmic sperm injection (ICSI), the sperm is used to fertilize the egg. The recovery is better for individuals with a higher level of follicle-stimulating hormone. The presence or absence of sperm cells can influence the outcome of testicular sperm extraction and Intra cytoplasmic sperm injection. Studies have shown that these procedures show only a 13 % success rate.
Conclusion
Sertoli cells help in spermatogenesis (a cell differentiation procedure responsible for sperm production). Seen in males of the age group between 20 and 40. Sertoli cells line the seminiferous tubules of the testis in Sertoli cell-only syndrome. The cause is mainly genetic, and diagnostic cells invoice semen analysis, blood tests, imaging, and biopsy. Treatment is mainly for infertility and does not involve the disease.
