Pathophysiology of PCOS during adolescence. The PCOS daughters model

Disturbances during intrauterine life have been implicated in the origin of PCOS and may modify the endocrine and metabolic function of a child born to a mother with PCOS . The concept of androgen exposure during pregnancy and further programming of PCOS in the offspring is based on several animal models and lately human evidence showing that daughters of androgenized females express many PCOS features during development .

To understand the sequence of appearance of the pathophysiological components of PCOS, some years ago our group designed a strategy that involved the assessment of daughters born to mothers with PCOS (PCOSd) at different stages of development. In several studies, we have described early metabolic and reproductive markers of the syndrome that may be modified through interventions that improve the adverse pregnancy environment of PCOS and through the control of acquired detrimental factors such as obesity in childhood and puberty . The recognition of these markers of PCOS and their order of appearance is very important to understand this condition during adolescence. We will use the PCOSd model in this section to approach this issue.

For systematizing purposes, we divide the pathophysiological components of PCOS into 4 groups that appear during development:

• (1)
  

  Ovarian dysfunction : Higher anti-Müllerian hormone (AMH, a marker reflecting the number of ovarian follicles) and increased ovarian volumes are two characteristic features of PCOSd . During early infancy (2–3 months old) and childhood (4–7 years old), PCOSd showed increased AMH levels . This is the first feature that can be recognized and is a very consistent marker in many studies, staying higher from puberty onwards and associated with increased ovarian volumes in PCOSd until adulthood . More importantly, AMH levels at the hypothalamus increase the pulse frequency of gonadotropin releasing hormone (GnRH) neurons leading to higher LH levels as recently shown in a mouse model were the female offspring of mothers treated with AMH during pregnancy showed this neuroendocrine feature , which may be modulated by hyperandrogenism as well as other environmental and genetic factors. These data link ovarian dysfunction with the next component.

  
  
• (2)
  

  Neuroendocrine dysfunction : In adolescents with PCOS, increased LH has been described as an early feature in the establishment of the syndrome . PCOSd exhibit elevated peak LH levels after leuprolide administration during early postnatal life and in late puberty. In Tanner stages IV and V, basal and postleuprolide stimulated LH concentrations are higher in PCOSd compared with control daughters . Similarly, postmenarcheal PCOS daughters exhibit elevated LH levels and LH to FSH ratio indicating that this neuroendocrine defect remains. Although these alterations are not observed in all adult women with PCOS, probably due to the effect of increased BMI, they seem to be a very strong marker during puberty and after menarche. In this regard, it has been observed that LH levels are negatively correlated with BMI and that obesity reduces the amplitude of the LH pulses , which explains why this feature tends to disappear during adulthood. On the other hand, LH levels are positively correlated with AMH levels in PCOSd during puberty , which supports the previously mentioned mechanism of AMH-stimulated GnRH increased pulse frequency as the current main explanation for this neuroendocrine feature in humans.

  
  
• (3)
  

  Hyperandrogenism : PCOSd exhibit higher basal and peak testosterone levels in Tanner stages IV and V compared to control girls . After menarche, basal testosterone levels and free androgen index (FAI) are higher in PCOSd, which is clinically reflected by an increased Ferriman-Gallwey score. Testosterone levels are associated with LH as it drives androgen production in the ovary and diminishes the ovarian-negative feedback regulation of LH . These findings also support data from animal models were the offspring of AMH-treated mothers also show higher testosterone and LH levels .

  
  
• (4)
  

  Hyperinsulinemia : The fourth component is a higher insulin response in the oral glucose tolerance test (OGTT), which may reflect metabolic disruption, one of the main determinants of the severity of PCOS expression. In this regard, insulin resistance, exacerbated by obesity, plays a major role in the metabolic abnormalities of this syndrome. Nevertheless, the relationship between androgens and insulin is reciprocal and there is evidence that androgens can induce insulin resistance . This feature can be observed before the onset of puberty when biochemical and clinical signs of hyperinsulinemia have been shown in PCOSd . Thus, this metabolic component appears early in life and during puberty it is exacerbated . Prepubertal and pubertal PCOSd show higher poststimulated insulin levels in a glucose tolerance test before the onset of hyperandrogenism, suggesting that insulin may play an early and pivotal role in the pathogenesis of PCOS . This feature remains during the postmenarcheal period and, during adulthood, is associated with key metabolic features commonly associated with PCOS, including increased BMI and larger waist circumference . More importantly, insulin resistance can be aggravated by childhood and pubertal obesity, poor eating habits, and lack of exercise, which are important factors that potentiate the expression of PCOS features during development .

  
  

  To show the importance of these models of fetal programming of PCOS on the clinical expression of this condition we evaluated the prevalence of PCOS on PCOSd. Using the Swedish Multi-Generational Register and the National Patient Register, daughters born to women with PCOS had a fivefold increased risk of being diagnosed with PCOS compared to daughters born to women without PCOS. Moreover, following up 21 Chilean daughters of women with PCOS until their twenties, 75% met the Rotterdam criteria for PCOS, showing higher BMI, larger waist circumference and higher diastolic blood pressure, demonstrating clinical metabolic dysfunction, and a higher Ferriman-Gallwey score and FAI, which are markers of clinical and biochemical hyperandrogenism along with higher AMH levels indicating an increased number of growing ovarian follicles . Thus, data regarding PCOSd reflect in a very close way the natural history of this condition and the presentation of PCOS during adolescence.

PCOS diagnosis during adolescence

Diagnosing PCOS during adolescence is challenging because some features of normal pubertal development such as irregular menstrual cycles, acne, and PCOS morphology on ultrasound, overlap with adult diagnostic criteria . Thus, delayed, under, over, or misdiagnosis are always surrounding our thoughts when we face an adolescent with the suspicion of PCOS. In an effort to solve this issue, evidence-based international guidelines were published in 2018 and recently reviewed by Peña et al. . We will use this evidence as a base to discuss this topic regarding each of the diagnostic features of PCOS:

• (1)
  

  Hyperandrogenism : This feature is probably the most important feature regarding PCOS diagnosis as it defines the severity and prognosis of this condition. During adolescence hirsutism, severe acne (more than 10 facial lesions), and/or biochemical hyperandrogenemia confirmed using validated high-quality assays are the most important manifestations of hyperandrogenism. In this regard, liquid chromatography-mass spectrometry or molecular tests validated by this technique, were not available, are very important to consider biochemical hyperandrogenism as a valid feature. The usual available tests used to measure total testosterone (T) are designed to diagnose male hypogonadism, which means that they have a linear behavior in a range 10 times higher than the values of women, thus they need to be adapted and validated to measure levels within women range. Androgen levels in adolescents reach adult levels around the time of menarche, nevertheless, local age and pubertal stage-adjusted reference values should be used to properly assess hyperandrogenemia in this setting . Regarding clinical hyperandrogenism, hirsutism is the preferred feature and has to be evaluated using the Ferriman-Gallwey (F-G) score. The cutoff point is defined according to ethnicity and usually values > 6–8 are considered abnormal which derive mainly from adult studies. In 15-year-old Chilean PCOSd, the median F-G score was 9.5 (5–15) compared to 6.5 (2.0–8.0) in control daughters , the latter value may seem high for control daughters but it reflects the Southern Spanish influence in the Chilean phenotype, this highlights the need for local cut-points to assess hirsutism to incorporate the genetic background and age of the studied population.

  
  
• (2)
  

  Irregular menstrual cycles : After menarche, the first menstrual cycles in women normally show a certain degree of irregularity despite many of these cycles are ovulatory in the early postmenarcheal years . Thus, when does this reflect ovarian dysfunction? Current guidelines consider the following irregular menstrual cycles to be pathologic according to years postmenarche :

  
  
  
  
  • –
    

    More than 90 days for any 1 cycle (> 1 year postmenarche).

    
    
  • –
    

    Cycles < 21 or > 45 days (> 1 to < 3 years postmenarche).

    
    
  • –
    

    Cycles < 21 or > 35 days (> 3 years postmenarche).

    
    
  • –
    

    Primary amenorrhea by age 15 or > 3 years postthelarche.

  
  
  
  

  It is suggested that menstrual cycle re-evaluation should be made 3 years postmenarche.

  
  
• (3)
  

  Ovarian morphology and AMH levels : Several studies have shown that the presence of a PCOM is very common during adolescence. Up to 40% of normal adolescents show this feature with no association with abnormalities in ovulatory rate, menstrual cycle duration, lipid levels, homeostatic model assessment, insulin resistance, or testosterone levels . The current consensus states that this criterion can only be used after 8 years postmenarche based mainly on the fact that the maximum ovarian volume is reached at age 20 and that transvaginal ultrasound studies establishing normal ovarian volumes and follicle counts have been mainly performed in women over 18 years old . In our studies in PCOSd, using transabdominal US, we observed higher ovarian volumes from Tanner stage I onwards along all Tanner stages . Nevertheless, the number of subjects was too limited to establish appropriate cutoff points for other populations. In a study by Villarroel et al., a > 10 mL ovarian volume was the best cutoff value in adolescents with PCOS, nevertheless, sensitivity was 76% and specificity was 84% . Thus, although not incorporated in current guidelines for adolescent PCOS diagnosis, ovarian volume can be useful as a complementary feature, always taking into account the clinical context of the patient.

  
  

  AMH levels reflect the number of small follicles in the ovary and are perfectly correlated with ovarian volumes and antral follicle US counts. In our studies, AMH levels have been found to be systematically higher in PCOSd . Nevertheless, appropriate population cutoff points in adolescents have not been established for the diagnosis of PCOS. Thus, this can be considered a useful tool in combination with the other clinical criteria, but not as a single diagnostic criterion for this condition .

  
  
• (4)
  

  Exclusion of other disorders that mimic PCOS : As in adults, endocrinologists should always search for alternative diagnosis that can simulate a PCOS. During adolescence, the most important conditions are pregnancy, glucocorticoid excess, nonclassic adrenal hyperplasia, hypothyroidism, and hyperprolactinemia . A complete accurate history and physical examination will usually point out the clues to rule out these conditions. Special attention should be given to the presence of muscular atrophy, the presence of thick-pigmented stretch marks, rapid installation of hirsutism, and the presence of virilization. Further study should be directed by clinical evaluation.

New approaches for the diagnosis and follow-up of PCOS during adolescence . New animal models combined with human data have shown strong insights about the programming and evolution of this condition. As pointed out in the first section, Risal et al. combining human and animal data showed that in utero DHT exposure in mice, independent of obesity, resulted in a transgenerational PCOS-like reproductive and metabolic phenotype in three generations (F1-F3) of female offspring. The differential gene expression was studied in oocytes of F1-F3 female mice identifying four genes (TIAL1, FABP5, RNF141, and INIP) that were also affected in serum samples from PCOSd and in unrelated women with PCOS. These findings provide evidence of a transgenerational effect in female offspring induced by the PCOS intrauterine environment and identify candidate serum markers that may predict a PCOS phenotype in future generations . The use of these markers may aid in the identification of adolescent patients who need closer follow-up and in the diagnosis of PCOS in this setting in the future. Further studies are needed to validate these markers to be used in clinical practice.

PCOS treatment during adolescence

One of the most important elements to be considered during adolescence in PCOS is prevention. Our research group has had the opportunity to follow up many PCOSd throughout development. Most of these girls (75%) develop PCOS in adulthood . One of the most important lessons we have learnt throughout these years is that, despite showing signs of hyperandrogenism during mid-puberty, girls that avoid increasing weight and keep a healthy lifestyle tend to develop a less severe syndrome when they become adults. As has been well documented in the literature, obesity is a pivotal triggering factor for this condition, and the prevalence of PCOS in adolescent groups with obesity is increased five times compared to normal weight groups . This is because obesity produces chronic systemic inflammation that increases insulin resistance and insulin levels, which at the same time potentiate ovarian hyperandrogenism perpetuating a vicious cycle that can be stopped through healthy lifestyle recommendations.

Thus, nutritional recommendations are very important. Increasing the amount of fiber in meals in which carbohydrates are going to be consumed, avoiding carbohydrates with a high glycemic index, and incorporating protein snacks are simple but effective recommendations. Daily exercise starting with a 30–40 min fast walk and increasing the intensity progressively until the patient is able to incorporate exercise as a stable practice is also a simple way to keep insulin resistance controlled.

Many of these patients show early signs of insulin resistance such as acanthosis nigricans, keratosis pilaris, and abdominal obesity. It is a common practice to order an OGTT with measurement of insulin in these patients. In this regard, we need to be careful because during adolescence insulin levels normally increase due to the effect of growth hormone. Thus, patients at this stage cannot be treated for insulin resistance based on insulin levels alone. The diagnosis of IR is clinical and has to be made taking into consideration mainly the elements that we already mentioned. Nevertheless, OGTT is very useful to evaluate glucose levels because it is not uncommon to see dysglycemia in these patients at this age, which need to be properly managed. The evaluation of insulin levels in the OGTT has to be made by a trained endocrinologist and may be useful for diagnosis and follow-up but never on their own, they are complementary tests that need to be interpreted in the clinical context of the patient.

Once lifestyle recommendations are being followed properly, the use of metformin is recommended in most of these patients, first to aid in the management of IR but also for the direct ovarian effects of metformin, where it reduces androgen production. On the other hand, metformin also has a central pituitary effect, reducing LH levels through the activation of AMPK . One of the problems we usually face with this treatment is gastrointestinal (GI) intolerance. Nevertheless, in our practice we have observed that when dietary recommendations are properly followed GI adverse reactions are significantly reduced. Another important issue is the dose, for an appropriate effect a daily dose of 1000–1500 mg should be given and maintained as long as clinical insulin resistance features are present.

The second pharmacologic tool we have is combined oral contraceptive pills (COCP), which are given to regulate menstrual cycles and to decrease the effects of hyperandrogenism. To obtain a full effect, the estrogen component is important to reduce LH secretion at the pituitary level. By reducing LH, the androgen production rate in the ovary is significantly reduced. High doses of ethinyl estradiol, which have been usually recommended at this age, have been recently associated with a reduced peak bone density in adolescents . In this regard, contraceptives with estradiol valerate, if available, may be the preferred choice nowadays. On the other hand, the associated progestin may or may not have a peripheral antiandrogenic effect. In this regard, there is concern about the thrombotic risk associated with certain antiandrogenic progestins such as cyproterone and drospirenone. The first one also has an added problem due to its glucocorticoid-like effect increasing insulin resistance. In current practice, progestins such as dienogest are considered well tolerated and have a good peripheral antiandrogenic effect. The later recommendations regarding the type of estrogen and progestin to use in PCOS are presented as a practical approach based on the recently published literature and clinical practice in adolescents. Nevertheless, appropriate evidence-based data are lacking regarding the best COCP for adolescents with PCOS, thus, current guidelines do not suggest a specific contraceptive to be used in this setting and literature has to be frequently revised regarding these drugs to stay updated in this area.

In cases with more severe hyperandrogenism, androgen receptor blockers such as spironolactone can be added with a starting dose of 50 mg bid. It is important to always add a contraceptive to avoid the teratogenic effect of this medication and also to avoid spotting, which usually occurs in women when they have spironolactone alone.

Most adolescent patients have a very good response to the combination of lifestyle measures and pharmacologic treatment. To choose the appropriate treatment, the priorities of the patient and specific components of the syndrome need to be balanced.

Central nervous system compromise in adolescents with PCOS

The brain expresses the AR, especially in areas crucial for learning, socializing, and memory such as the hippocampus, prefrontal cortex (PFC), amygdala, and hypothalamus . Women with PCOS have worse performance in tests of verbal fluency, verbal memory, and visuospatial working memory , and exhibit increased anxiety compared to control women, which is normalized after treatment of hyperandrogenism. Adult patients with PCOS show a broad spectrum of CNS compromise, from subtle changes in the microstructure of the brain to mental health disorders such as anxiety and depression , many of these features may be programmed by exposure to androgens during prenatal and pubertal life. Thus, adolescence is a critical period for mental health in the PCOS setting.

Daughters of women with PCOS scored higher in parent-report autistic trait questionnaires at 4–11 years old, which was correlated with the amniotic fluid levels of testosterone of their mothers during pregnancy . Other studies have shown that higher testosterone exposures are linked with lower empathic responses and both daughters and sons of mothers with PCOS have an increased risk of autism spectrum disorder (ASD) .

Puberty and adolescence are considered a plasticity window , during which genetic and epigenetic changes, hormones, early life experiences, environmental cues, among many other factors, will induce modifications in brain function and connectivity . During puberty, there are many changes in neurons and glia, with a number of neural plasticity mechanisms in which steroid hormones, like androgens, play a fundamental role . These changes occur at different times on each brain region following a predetermined schema and timeline inducing an interregional influence that is necessary to produce synchronized responses , that are the basis of behavioral outputs . This view of functional brain development is known as the “Triadic Neural System Model” , which states that the PFC, striatum, and amygdala, which are part of a network affected in androgen exposed animal PCOS models , are the key components of motivated behavior. These systems mature along a predetermined order, whereas the PFC develops linearly, increasing its inhibitory effect with age, the striatum and amygdala show a hyper or hypo response to threatening or rewarding contexts during adolescence . The activity of both systems reaches similar levels and shows a fully coordinated response by the end of adolescence .

Sex steroids have an impact on this development timeline, in this regard, the normal increase in testosterone levels during a 2-year period of pubertal maturation is associated with an increase of brain activity in the amygdala in boys and girls, which is due to a decreased connectivity between the amygdala and the orbitofrontal cortex (OFC, part of the PFC). Adolescents with a large increase in testosterone (but within the normal range for age) exhibited positive amygdala-OFC connectivity at the initial evaluation, which became decoupled 2 years later and was associated with increased levels of withdrawal temperament, consistent with an increase in threat sensitivity . In a recent metaanalysis, one specific cluster in the OFC was identified as the main site of testosterone action in this system during adolescence . Hence, puberty is a limited organizational window that constitutes a critical period during which androgens can trigger permanent structural and functional changes. These changes will affect the connectivity of the brain, modulating adult behavior in several ways . These functions have not been studied during puberty in the context of female hyperandrogenism. Thus, this is an area of active investigation. In the next years, we will probably have more data regarding this fascinating topic. In the meantime, guidelines recommend screening for anxiety and depression at this age in the context of PCOS. Appropriate management of PCOS especially hyperandrogenism in adolescence may be key to prevent the development of mental disease later on.