Polycystic ovarian disease

Comparative efficacy of metformin combined with cabergoline versus metformin alone in patients with PCOS and hyperprolactinemia: A systematic review and meta-analysis of randomized controlled trials

Isntroduction. Polycystic ovary syndrome (PCOS) is a multifaceted endocrine-gynecological condition affecting a substantial number of women during their reproductive years. Metformin (MET) has been shown to improve ovarian function in PCOS-related conditions, while cabergoline is recognized for its powerful and sustained ability to reduce prolactin levels. This study investigates the potential impact of combining cabergoline with metformin while comparing it with metformin alone in the treatment of PCOS alongside hyperprolactinemia.

METHOD

To gather data, we searched PubMed, Google Scholar, ScienceDirect, and Cochrane Central. Eligible studies were randomized controlled trials involving patients with PCOS and hyperprolactinemia. Outcome measures included changes in the levels of prolactin, testosterone, DHEAS, BMI and menstrual irregularities. RevMan version 5.4 was used to analyze outcomes.

RESULT

This study incorporated three Randomized Controlled Trials (RCTs) involving 405 participants in total. Patients receiving a combination of metformin and cabergoline experienced significant reductions in prolactin and testosterone levels (p= <0.0001 and p=<0.0001, respectively). Conversely, alterations in DHEAS levels and BMI did not reach statistical significance (p = 0.19 and p = 0.71, respectively). Notably, women solely prescribed metformin exhibited significantly higher rates of menstrual irregularities compared to those receiving both metformin and cabergoline (p=<0.0001).

CONCLUSION

Our analysis underscores the synergistic effect achieved by pairing metformin and cabergoline in patients with PCOS and hyperprolactinemia. However, we encountered only a restricted number of studies meeting our criteria. It is imperative to consistently assess the combined effects of metformin and cabergoline to gain deeper insights into their effectiveness in addressing PCOS and hyperprolactinemia.

PCOS and Hyperprolactinemia: what do we know in 2019?

Polycystic ovary syndrome (PCOS) and hyperprolactinemia (HPRL) are the two most common etiologies of anovulation in women. Since the 1950s, some authors think that there is a pathophysiological link between PCOS and HPRL. Since then, many authors have speculated about the link between these two endocrine entities, but no hypothesis proposed so far could ever be confirmed. Furthermore, PCOS and HPRL are frequent endocrine diseases and a fortuitous association cannot be excluded. The evolution of knowledge about PCOS and HPRL shows that studies conducted before the 2000s are obsolete given current knowledge. Indeed, most of the studies were conducted before consensual diagnosis criteria of PCOS and included small numbers of patients. In addition, the investigation of HPRL in these studies relied on obsolete methods and did not look for the presence of macroprolactinemia. It is therefore possible that HPRL that has been attributed to PCOS corresponded in fact to macroprolactinemia or to pituitary microadenomas of small sizes that could not be detected with the imaging methods of the time. Recent studies that have conducted a rigorous etiological investigation show that HPRL found in PCOS correspond either to non-permanent increase of prolactin levels, to macroprolactinemia or to other etiologies. None of this recent study found HPRL related to PCOS in these patients. Thus, the link between PCOS and HPRL seems to be more of a myth than a well-established medical reality and we believe that the discovery of an HPRL in a PCOS patient needs a standard etiological investigation of HPRL.

Role of Prolactin in the Polycystic Ovary Syndrome

Studies with a dopamine agonist (Bromocriptine) and an antagonist (Haloperidol) suggest that elevated sex steroid synthesis such as may be found in the polycystic ovary syndrome (PCO) influence the pituitary lactotrope response to endogenous control mechanisms. A distinction between PCO with occasional elevation of plasma prolactin (PRL) and the galactorrhoea-amenorrhoea syndrome (GA) associated with hyperprolactinaemia can be established on the basis of differences in circulating levels of sex steroids and in the pattern of response to lactotrope cell stimulation. Thus, adrenal androgen synthesis can be strengthened in GA whereas in PCO both pathways, adrenal and ovarian, may be overstimulated. Also blunted PRL response to TRH or dopaminergic blockade is often seen in GA. The use of bromocriptine in patients with PCO and elevated PRL plasma levels has been shown to restore ovulation. The possible implications of dopaminergic mechanisms in the control of LH secretion independent of PRL release are discussed.

Polycystic ovary syndrome and hyperprolactinemia are distinct entities

The aims of the present study were to identify the cause of hyperprolactinemia in polycystic ovary syndrome (PCOS) and to compare prolactin (PRL) levels between PCOS women without hyperprolactinemia and women with insulin resistance and without PCOS. A group of 82 women (age: 27.1 +/- 7.6 years) with PCOS was included in the study. Their PRL levels were measured and compared with those of women with insulin resistance without PCOS (controls; n = 42; age: 29.2 +/- 8.2 years). Among the 82 PCOS women, 13 (16%) presented high PRL levels (103.9 +/- 136.0 microg/l). The causes of hyperprolactinemia were: pituitary tumor (responding to cabergoline) in nine cases (69%; PRL range: 28.6 - 538 microg/l); oral hormonal contraceptive treatment in two cases (15%; PRL: 46 and 55 microg/l, respectively); and use of buspirone and tianeptine in one case (8%; PRL: 37.1 microg/l); one case (8%; PRL: 34.4 microg/l) had macroprolactinemia. In drug-induced hyperprolactinemic patients PRL levels normalized after treatment interruption. The average PRL level in the 69 remaining patients was 12.1 +/- 5.5 microg/l, a value not statistically different from that of the control group (11.8 +/- 4.9 microg/l). This result leads us to conclude that PCOS patients with increased PRL levels must be investigated for other causes of hyperprolactinemia, because hyperprolactinemia is not a clinical manifestation of PCOS.

Increased prolactin response to TRH in polycystic ovary syndrome with low basal prolactin values

An intravenous TRH loading test with 200 micrograms TRH was carried out in 9 hypoprolactinemic (serum prolactin less than 100 mIU/ml) and 6 normoprolactinemic PCO patients and 6 normal subjects. Basal and stimulated prolactin and TSH levels were measured. The latter were within normal values. Prolactin responses to TRH were exaggerated in PCO patients, irrespective of the basal prolactin values. According to literary data, these results indicate that increased prolactin response to TRH in PCO is independent of the basal prolactin values and suggest disturbed tuberoinfundibular dopaminergic function.

The role of hyperinsulinemia in the pathogenesis of ovarian hyperandrogenism

The evidence that supports the hypothesis that insulin and LH both regulate ovarian androgen production was presented. The most dramatic clinical example of the association between hyperinsulinemia and hyperandrogenism is the HAIR-AN syndrome. Our hypothesis is that, in the HAIR-AN syndrome, the severe insulin resistance causes a compensatory hyperinsulinemia, which stimulates ovarian androgen production if adequate LH is present. The acanthosis nigricans is an epiphenomenon of the syndrome. Acanthosis nigricans is a dermatologic manifestation of severe insulin resistance. In vitro evidence suggests that insulin and IGF-I stimulate androgen production in incubations of human stroma and theca. The stromatropic effects of insulin may sensitize the stroma to the stimulatory effects of LH. In some hyperandrogenic-insulin-resistant women, a glucose load appears to produce an acute rise in circulating androgens. The magnitude of the rise in circulating androgens is proportional to the magnitude of the insulin response to the glucose load. These data suggest that hyperinsulinemia may play a central role in the development of ovarian hyperandrogenism.

Decrease of circulating level of SHBG in postmenopausal obese women as a risk factor in breast cancer: reversible effect of weight loss

Levels of circulating estrone (E1), estradiol (E2), androst-4-ene-3,17-dione (Adione), 3,5,3'-triiodothyronine (T3), thyroxine (T4), and sex hormone-binding globulin (SHBG) were measured in 10 obese postmenopausal patients with breast cancer and in 10 obese postmenopausal control subjects matched for age, body size, and menopausal status. T3, T4, and SHBG were also measured in 10 lean postmenopausal control subjects. In cancer patients after mastectomy, the cytosolic estrogen receptors (E2R) in tumor specimens were determined. No significant differences between the two groups of obese postmenopausal women were found for levels of all determinations carried out in serum. Comparing obese subjects (with or without breast cancer) with lean controls, circulating levels of T3 were found approximately 50% higher in the obese group. Conversely, SHBG was found around 50% of the value observed in lean controls. The changes presumably produced by obesity on serum SHBG levels appear to be reversible, tending toward normality with weight reduction. In cancer patients SHBG correlated negatively with cytosolic E2R concentrations (P less than 0.01). In conclusion, it is considered that obesity implies a double risk for breast cancer in susceptible postmenopausal women, by inducing a decrease of SHBG and a concomitant increase of the supply of "free" E2 to target tissues, in absence of cyclic endogenous progesterone.

Pituitary and ovarian responses to LHRH stimulation in women with clinical features of the polycystic ovary syndrome

The gonadotrophin release and the changes in ovarian and adrenal steroid levels following the administration of a low dose of LHRH were assessed in a group of women with clinical features of the polycystic ovary syndrome (PCO syndrome). The results were compared with those obtained in a group of normal ovulatory women. A significant increase in LH and FSH levels and a decrease in cortisol concentrations were demonstrated in both study groups following the administration of LHRH. The LH response was significantly exaggerated in the PCO group when compared with the control women. The estrone and estradiol levels did not change in either group. The androstenedione and testosterone concentrations did not change or decreased in the control group, whereas an increase of these hormones was seen in the PCO group. In the PCO group a positive correlation between the LH response and the androstenedione response was noticed. These findings indicate that the hyperandrogenic state encountered in PCO patients is at least in part of ovarian origin.

Hormonal characteristics of women with clinical features of the polycystic ovary syndrome

The aim of the present study was to determine whether a group of patients selected on the basis of clinical features only is characterized by the typical hormonal findings as discussed in the literature concerning the PCO-syndrome. PCO patients had oligomenorrhea, secondary amenorrhea or otherwise evidence of chronic anovulation, as well as hirsutism and/or obesity. Control women had regular menstrual cycles and a normal body weight. Since androgen and estrogen production in women depends on the stage of follicular development, an effort was made to obtain endocrinological data under standardized conditions. Under well-defined circumstances the PCO group (n = 20) had higher LH levels and lower FSH levels as compared with the control group (n = 10). Consequently the LH/FSH ratio was significantly elevated in the PCO group. Serum estrone and estradiol levels were significantly elevated in the PCO group, as were the serum levels of androstenedione and testosterone. Despite these differences a marked degree of overlap existed in the PCO patients and the control women for gonadotropin, estrogen and androgen levels. It was concluded that although the presence of polycystic ovaries in the investigated PCO group of women was not confirmed by laparoscopy, laparotomy or histological examination of the ovaries, these women had basal endocrinological characteristics similar to those found in well-proven PCO patients reported in the literature.

Pathological mechanisms in polycystic ovary syndrome: modulation of LH pulsatility by progesterone

The pulsatile discharge of luteinizing hormone (LH) in nine patients with polycystic ovary syndrome (PCO) and nine patients with amenorrhoea but without PCO, who exhibited LH discharge in response to oestrogen provocation, were studied by 4-h measurement of gonadotrophin pulsatility before and after a course of progesterone injections. No significant differences were found in the gonadotrophin pulsatility patterns of the two groups, although the LH/FSH ratio rose significantly in the patients without PCO after progesterone but not in the patients with PCO, suggesting an abnormality of FSH storage. The ability to discharge gonadotrophins in response to oestrogen provocation has been reported to be present in patients with greater than or equal to 3 LH pulses in a 4-h study period. This, however, was not demonstrated in five of the nine PCO patients despite the presence of 'normal' gonadotrophin pulsatility patterns.

Polycystic ovarian disease: ultrasonic evaluation and correlations with clinical and hormonal data

The size, shape, margins, and structure of the ovaries, as observed in 26 patients with polycystic ovarian disease were analyzed, and uterine/ovarian ratio (maximum antero-posterior diameter of uterine fundus divided for longitudinal diameter of ovary) was calculated. The maximum surface area of the organs ranged from 9.5 cm2 to 17.3 cm2 (average value 12.9 cm2). A "roundness index" (minimum diameter X 100/maximum diameter) was calculated in order to evaluate the shape: it ranged from a value of 100 in perfectly rounded ovaries to a value of 54 in ovaries of oval shape. The ovarian structure was characterized by many small cysts of the same dimensions in 19 cases; in two patients there was a predominant cyst; in five cases it appeared as many thick echoes arranged along parallel lines. The uterine/ovarian ratio was always equal to or less than 1. Correlation tests for size, shape of the ovaries, patient's age, and duration of symptoms were highly significant. This leads one to suppose that both of these ultrasonic findings are a function of the duration of the disease and that polycystic ovarian disease, once established, is the cause of progressive enlargement of these organs.

Peripheral aromatization as a risk factor for breast and endometrial cancer in postmenopausal women: a review

In menopause, estrogens are produced almost exclusively through peripheral aromatization of androgens, especially androstenedione. Obesity increases the production rate of estrogens by means of the same mechanism. In postmenopause, plasma levels of SHBG diminish significantly. Obesity even further decreases the levels of SHBG, thus increasing "free" E2 available to target tissues. The increase in circulating estrogenic activity in menopause, whether as a result of obesity or of ingestion of estrogens, implies a risk factor for endometrial and breast cancer not only because of the permissive and stimulating effects of estrogens but also due to the special circumstance that they may act on target tissues in the almost absolute absence of the "protecting effect" of progesterone. The modifications performed by obesity on the values of SHBG and circulating estrogens are reversible, since they tend to normalize with weight loss.

Acth function in women with the polycystic ovarian syndrome

Serum androgen levels, including dehydroepiandrosterone sulphate (DHAS) which is thought to be solely of adrenal origin, are elevated in women with the polycystic ovarian syndrome. We have investigated the possibility that this may be due to a mild form of congenital adrenal hyperplasia by measuring basal and stimulated levels of ACTH in women with this condition and have compared them to levels in normal women. We found no difference in the diurnal rhythm of ACTH between patients and normal subjects nor any difference in stimulated levels achieved after a single-dose oral metyrapone test. Thus there is no evidence from this study to support the idea that these patients might have congenital adrenal hyperplasia. There are two alternative hypotheses to explain the elevated DHAS levels. They may be associated with the high oestrogen levels, which interfere with the enzyme 3 beta-hydroxysteroid dehydrogenase, or there may be alteration of the factors controlling adrenal androgen secretion.

Circulating testosterone, sex hormone binding globulin and prolactin in women with late onset or persistent acne vulgaris

Serum testosterone, sex hormone binding globulin (SHBG) and prolactin were measured in thirty-eight women with acne which persisted or started after the age of 18 years. One or more of these levels were abnormal in 76% of patients. Increased testosterone or low SHBG were present alone or in combination in 60% of patients. This group was presumed to have a raised level of non-protein bound, metabolically-available testosterone. Hyperprolactinaemia, which was present in 45% of patients, may be important in view of the reported association with increased adrenal androgens. The hormonal abnormalities may be causally related to the acne and a greater understanding of them may lead to better treatment.

Primary amenorrhea associated with hirsutism, acanthosis nigricans, dermoid cysts of the ovaries and a new type of insulin resistance

We describe a 15 1/2 year old presenting with primary amenorrhea, hirsutism, acanthosis nigricans and insulin resistance. Ovarian vein catheterization studies revealed bilateral excess plasma testosterone and androstenedione secretion, and at surgery multiple dermoid cysts of both ovaries were found in association with polycystic ovaries. The suggestion that the dermoid cysts may be causative in the evolution of the polycystic ovarian disease has been made. The mechanism of the insulin resistance appears to be at the post receptor level. The acanthosis nigricans diminished following surgery with normalization of the plasma androgens.