Replacement of Male Mini-Puberty

Dimitrios T. Papadimitriou; Dionysios Chrysis; Georgia Nyktari; George Zoupanos; Eleni Liakou; Anastasios Papadimitriou; George Mastorakos

Disclosures

J Endo Soc. 2019;3(7):1275-1282. 

In This Article

Discussion

Daily subcutaneous injections for 3 months of the commercially available recombinant human LH (75 IU) plus FSH (150 IU) preparation mimics neonatal male mini-puberty, successfully repairing micropenis as well as bilateral cryptorchidism either in the inguinal or the intra-abdominal position. We acknowledge the limited number of patients in the REMAP study. Nonetheless, given the estimated prevalence of CHH at 1:5000 births[26] with the genetic basis still being uncovered in about half the cases studied,[8] our prospective interventional 10-year single-center study has included the highest number of patients published so far, at least to our knowledge.[27] Although we did not perform genetic analysis for the specific candidate genes in our cohort, there was confirmation of CHH with at least three repeated measurements at 8 hours of undetectable LH, FSH, and testosterone from 15 days of life up to 3 months of age,[15] proving the lack of the physiological male mini-puberty. Moreover, all patients included had micropenis and bilateral cryptorchidism.

This noninvasive strategy is safe because there are no side effects and because the possibility of an unsuccessful surgery or postsurgical testicular atrophy is spared. This strategy also costs far less than the estimated $18,000 for 6 months of treatment with rLH and rFSH using an insulin pump[27] and even less than two surgical operations, calculated to be at least $5000 each.[28] Furthermore, up to 50% of testicles in the intra-abdominal position may require a laparoscopic two-stage operation,[29] requiring three or four operations in bilateral cryptorchidism. Moreover, this treatment strategy has a short duration, it can be administered at home by the parents using a commercially available LH/FSH preparation, and it likely preserves fertility. It may be as important to the brain as to the testes because fetal Leydig cells produce the high levels of androgen (testosterone or androstenedione, depending upon the species) required for differentiation of male genitalia and masculinization of the brain,[30] influencing human neurobehavioral development.[31] In CHH with the fetal gonadotropic surge being missed, replacement of mini-puberty may be of crucial importance to the masculinization of the brain. In fact, emerging evidence suggests that the early postnatal period is important as well.[31] Regarding somatic growth, boys show greater linear growth velocities through their first 6 months of life than girls, with the greatest difference observed at the time of peak testosterone production,[32] implying that replacement of mini-puberty in CHH may play an important role in infants' growth.

The first attempt to repair micropenis and cryptorchidism involved recombinant human (rh)LH and FSH in doses of 20 and 21.3 IU SC, respectively, twice weekly for 5 months in an 8-month-old boy diagnosed with CHH. Whereas serum testosterone remained undetectable, penile length and testicular volume increased significantly.[33]

The work of reference came from Bougnères et al.[11] in St Vinvent de Paul Hospital in Paris: two neonates, one with hypotuitarism (patient 1) and one with CHH (patient 2), both with micropenis and microorchidism, received LH and FSH with continuous subcutaneous injection with an insulin pump: patient 1 from the age of 8 weeks for 4 months at a mean infusion rate of 56 IU rhLH and 67 IU of rhFSH per day (for a total dose of 6720 IU of LH and 8040 IU of FSH) and patient 2 from the age of 20 weeks for 6 months at a mean infusion rate of 50 IU rhLH and 125 IU rhFSH per day (for a total dose of 9000 IU of LH and 22,500 IU of FSH). The results led to serum testosterone (which was previously undetectable) levels that are normal for mini-puberty, normal LH, and high FSH levels, with normalization of AMH and inhibin-b levels. Micro-orchidism and micropenis were successfully resolved. Another more recent publication from the same group reported eight patients aged 6.03 ± 3.75 months (range, 0.25 to 11 months) receiving recombinant LH at a total dose of 7000 IU and recombinant FSH up to 21,000 IU with a subcutaneous pump for 6 ± 0.58 months at a total cost of $18,000.[27] The investigators increased the FSH daily dose to 150 IU to force Sertoli cells to produce AMH and inhibin B at a more physiological level, based on their previous experience.[11] The authors speculated that, in patients with CHH born with cryptorchidism, there may be some resistance of Sertoli cells to FSH, possibly because of the prolonged lack of exposure to pituitary FSH during prenatal life. Regarding the deleterious effect that high circulating gonadotropins might have on germ cells in cryptorchid testes, Lambert and Bougneres[27] argue that such deleterious effects have only been reported in boys with idiopathic cryptorchidism (with or without primary testicular insufficiency) treated with hCG, not in the CHH population or in response to rhLH or rhFSH.

In our series, the total dose administered to each patient was 6750 IU of LH and 13,500 IU of FSH, analogous to that of Bougnères et al..[11] Our results in testosterone, LH, FSH, AMH, and inhibine-b levels, as well as in penile length and testicular volume, were in accordance with their results, aiming to normalize AMH and inhibin-b secretion from Sertoli cells. However, in our series, all patients had bilateral crypto-orchidism rather than micro-orchidism, with both testes in the intra-abdominal and/or inguinal position. Furthermore, the duration of our study was limited to 12 weeks, and the treatment was performed at home by the parents, simplifying the procedure as much as possible. The supranormal FSH levels had no obvious side effects to the patients and their testicular architecture, at least to the extent that a high-quality ultrasound could disclose. These FSH levels may be of benefit because in CHH there is complete absence of the subtle normal gonadotropin levels that are normally observed during childhood, the absence of which results in a reduction in testicular volume after completion of therapy but with testes remaining in the scrotal position up to 10 years after the initial intervention. Although two patients required unilateral orchidopexy because two testes regressed to the low inguinal area a few months later, the surgical procedure was fast and easy and was successfully performed by experienced hands in a day clinic.

Regarding the latest guidelines for the management of undescended testes from the European Association of Urology/European Society for Pediatric Urology[34] and the American Urological Association,[35] no consensus exists on the various forms of hormonal treatment, which are to be assessed on an individual basis only. Providers should not use hormonal therapy to induce testicular descent because evidence shows low response rates and a lack of evidence of long-term efficacy. Hence, an appropriate specialist (i.e., a pediatric endocrinologist) should be consulted for all phenotypic male newborns with bilateral, nonpalpable testes for evaluation of a possible disorder of sex development. Although there are no reports on long-term fertility outcomes of isolated hormonal therapy, the latter may optimize germ cell maturation and/or sperm production because LHRH or hCG administration prior to orchidopexy has been shown to improve the fertility index on biopsies obtained at the time of orchidopexy.[35] The finding that neoadjuvant gonadotropin-releasing hormone therapy before surgery may improve the fertility index in undescended testes was proven by a prospective randomized trial,[36] in which a total of 42 boys at median age of 33.5 months with unilateral (21 patients; median age, 34 months) or bilateral cryptorchidism (21 patients; median age, 34 months) received intranasal gonadorelin (1.2 mg/d) for 4 weeks before orchidopexy (30 testes; median patient age, 32 months) vs surgery alone (33 testes; median patient age, 47 months). In this trial, statistical significance in the fertility index was only observed in boys treated before the age of 2 years (P = 0.03), whereas in bilateral cryptorchidism the mean fertility index was significantly higher after hormonal treatment: 0.96 (SD ± 0.47; range, 0.5 to 2) vs 0.56 (SD ± 0.38; range, 0 to 1.12) without hormonal stimulation. Although a decrease in total Leydig cell population was noted in all cases, in older boys preoperative GnRH therapy was equally beneficial, although normal testis histology was not restored. On the other hand, the outcome of the operated testes is well described in the literature: ~4% of the nonpalpable testes failed the operation, and another 2% presented atrophy after orchidopexy.[35] In a subset of bilateral hypoplastic testes in intra-abdominal position due to CHH, the failure percentage is expected to be even higher.

To study the future fertility in male CHH, Bouvattier et al.[37] comprehensively reported that standard treatments, usually started after the onset of puberty, often only partially corrected the genital abnormalities and spermatogenesis. In children, interventions and particular hormone replacement therapy protocols have been historically directed at virilizing the patient,[38] maximizing height potential, and minimizing psychosocial morbidity, although issues of future fertility have decreased.[39] Therefore, treatment with gonadotropins during the neonatal period not only corrects genital hypotrophy and restores testicular endocrine function but might also improve the response to future treatments intended to restore fertility.[37] Early intervention, such as neonatal gonadotropin therapy mimicking mini-puberty, may improve testicular function and genital development.[40] Furthermore, because of the weak expression of the androgen receptor in infant Sertoli cells, administration of hCG/LH instead of an hCG/LH+FSH combination would not result in sufficient Sertoli cell maturation beneficial to future spermatogenesis.[11,37,41] The importance of the physiological gonadotropin surge in the fetal life (8 to 24 weeks) and early postnatally (15 days to 3 months) in the male sex development and the masculinization of the brain should be taken into account.[42]

With the current availability of rhLH and rhFSH, as well as their combination, in pens, analogous to that of insulin delivery devices, puberty induction protocols may be planned and implemented with daily subcutaneous administration of rhLH/FSH, establishing the optimal LH/FSH ratio, dosage, and frequency of administration. Another interesting alternative[43] would be the use of a commercial preparation of recombinant human chorionic gonadotrophin (Ovitrelle)[44] combined with the long-acting FSH agonist corifollitropin alfa (Elonva)[45] injected once a week in gradually increasing doses. A more physiological approach like this might further improve future fertility than more complex protocols with rhCG, rhFSH, and long-acting testosterone;[40] may be safer to the testicles than high doses of hCG;[46] and may have better outcomes in terms of pubertal maturation and adult height attainment than by supplying directly testosterone as the end product, even though long-acting testosterone undecanoate IM injections offer advantages in terms of smoother pharmacokinetics and adherence can be optimized by combining monitoring and dose administration into a single visit.[47] In our experience, the latter approach in pubertal induction is easy to implement with excellent adherence in hypogonadal boys but leaves the problem of future fertility unsolved.

Further studies are needed to evaluate our strategy and to test its effectiveness in other hypogonadic pathologies, such as idiopathic bilateral cryptorchidism and Pradder-Willi syndrome.

In summary, timely replacement of the neonatal male mini-puberty by daily SC injections of the commercially available rhLH (75 IU)/rhFSH (150 IU) for 3 months repairs even intra-abdominal cryptorchidism safely and cost-effectively, inducing high/normal activation of Sertoli and Leydig cells. This strategy corrects genital hypotrophy, restores testicular endocrine function, and may improve the response to future treatments intended to induce fertility.

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