Absence of major fibrotic adverse events in hyperprolactinemic patients treated with cabergoline

First-line surgery in prolactinomas: lessons from a long-term follow-up study in a tertiary referral center

CONTEXT

Although consensus guidelines recommend dopamine agonists (DAs) as the first-line approach in prolactinomas, some patients may opt instead for upfront surgery, with the goal of minimizing the need for continuation of DAs over the long term. While this approach can be recommended in selected patients with a microprolactinoma, the indication for upfront surgery in macroprolactinomas remains controversial, with limited long-term data in large cohorts. We aimed at elucidating whether first-line surgery is equally safe and effective for patients with micro- or macroprolactinomas not extending beyond the median carotid line (i.e., Knosp grade ≤ 1).

METHODOLOGY

Retrospective study of patients with prolactinomas Knosp grade ≤ 1 treated with upfront surgery. The primary endpoint was patients' dependence on DAs at last follow-up. The secondary endpoint was postoperative complications. Independent risk factors for long-term dependence on DAs were analyzed.

RESULTS

A microadenoma was noted in 45 patients (52%) and a macroadenoma in 41 (48%), with 17 (20%) harboring a Knosp grade 1 prolactinoma. Median follow-up was 80 months. First-line surgery resulted in long-term remission in 31 patients (72%) with a microprolactinoma and in 18 patients (45%) with a macroprolactinoma (p = 0.02). DA therapy was ultimately required in 11 patients (24%) with microadenomas vs. 20 (49%) with macroadenomas (p = 0.03). As for the latter, DA was required in 13 patients (76%) with Knosp grade 1 macroadenomas vs. 7 patients (29%) with Knosp grade 0 macroadenomas (p = 0.004). There was no mortality, and morbidity was minimal. Knosp grade 1 prolactinomas (OR 7.3, 95% CI 1.4-37.7, p = 0.02) but not adenoma size (i.e., macroprolactinomas) were an independent predictor of long-term dependence on DAs.

CONCLUSIONS

First-line surgery in patients with microprolactinomas or macroprolactinomas Knosp grade 0 resulted in a good chance of non-dependency on DA therapy. However, in patients with prolactinomas Knosp grade 1, first-line surgery cannot be recommended, as adjuvant DA therapy after surgery is required in the majority of them over the long term.

A scoping review to understand the indications, effectiveness, and limitations of cabergoline in radiological and biochemical remission of prolactinomas

Cabergoline has long been used in the medical management of prolactin-secreting pituitary adenomas. However, there is contradicting and inadequate evidence on the efficacy of cabergoline in achieving radiological and biochemical remission in prolactinoma. This article presents scoping review of evidence in cabergoline achieving radiological and biochemical remission in cases of prolactinoma. We have used a recommended scoping review methodology to map and summarize existing research evidence and identify knowledge gaps. The review process was conducted according to the PRISMA-ScR guidelines (Preferred Reporting Items for Systematic reviews and Meta-Analyses Extension for Scoping Reviews). The selection of studies was based on the criteria defined. Essential information such as reference details, study characteristics, topics of interest, main findings, and the study author's conclusion are presented in text and tables. With the study selection process, eight publications were finally included-one systematic review and meta-analysis, one RCT, and six primary studies. Cabergoline is effective in achieving biochemical and radiological remission in cases of prolactinoma. We identified several knowledge gaps with the scoping review and directions for future studies. Future studies, including randomized studies, will help address challenging questions associated with the management of prolactinoma.

The risks of medical treatment of prolactinoma

First-line treatment of prolactinoma is usually medical, based on dopamine agonists receptors, mainly cabergoline. The classical side-effects of cabergoline (low blood pressure and nausea) have been well known since it was first introduced. Other side-effects, however, are more controversial or simply less frequent, but need to be considered during monitoring. This review will focus on these side-effects: cardiac valvular fibrosis, pleural, pericardial and retroperitoneal fibrosis, addictive/compulsive behaviors, and risks secondary to significantly decreased tumor volume. We will also describe how such side-effects should be monitored and managed. In our opinion, the low prevalence of these side-effects should not cast doubt on the role of cabergoline in the therapeutic algorithm of prolactinoma.

Echocardiography and monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia: A joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology

This is a joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology on the role of echocardiography in monitoring patients receiving dopamine agonist (DA) therapy for hyperprolactinaemia. Evidence that DA pharmacotherapy causes abnormal valve morphology and dysfunction at doses used in the management of hyperprolactinaemia is extremely limited. Evidence of clinically significant valve pathology is absent, except for isolated case reports around which questions remain. Attributing change in degree of valvar regurgitation, especially in mild and moderate tricuspid regurgitation, to adverse effects of DA in hyperprolactinaemia should be avoided if there are no associated pathological changes in leaflet thickness, restriction or retraction. Note must be taken that even where morphological change in leaflet structure and function may be suspected, grading is semi-quantitative on echocardiography and may vary between different machines, ultrasound settings and operators. Decisions regarding discontinuation of medication should only be made after review of serial imaging by an echocardiographer experienced in analysing drug-induced valvulopathy or carcinoid heart disease. A standard transthoracic echocardiogram should be performed before a patient starts DA therapy for hyperprolactinaemia. Repeat transthoracic echocardiography should then be performed at 5 years after starting cabergoline in patients taking a total weekly dose less than or equal to 2 mg. If there has been no change on the 5-year scan, repeat echocardiography could continue at 5-yearly intervals. If a patient is taking more than a total weekly dose of 2 mg, then annual echocardiography is recommended.

Echocardiography and monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia: a joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology

This is a joint position statement of the British Society of Echocardiography, the British Heart Valve Society and the Society for Endocrinology on the role of echocardiography in monitoring patients receiving dopamine agonist (DA) therapy for hyperprolactinaemia. (1) Evidence that DA pharmacotherapy causes abnormal valve morphology and dysfunction at doses used in the management of hyperprolactinaemia is extremely limited. Evidence of clinically significant valve pathology is absent, except for isolated case reports around which questions remain. (2) Attributing change in degree of valvular regurgitation, especially in mild and moderate tricuspid regurgitation, to adverse effects of DA in hyperprolactinaemia should be avoided if there are no associated pathological changes in leaflet thickness, restriction or retraction. It must be noted that even where morphological change in leaflet structure and function may be suspected, grading is semi-quantitative on echocardiography and may vary between different machines, ultrasound settings and operators. (3) Decisions regarding discontinuation of medication should only be made after review of serial imaging by an echocardiographer experienced in analysing drug-induced valvulopathy or carcinoid heart disease. (4) A standard transthoracic echocardiogram should be performed before a patient starts DA therapy for hyperprolactinaemia. Repeat transthoracic echocardiography should then be performed at 5 years after starting cabergoline in patients taking a total weekly dose less than or equal to 2 mg. If there has been no change on the 5-year scan, repeat echocardiography could continue at 5-yearly intervals. If a patient is taking more than a total weekly dose of 2 mg, then annual echocardiography is recommended.

Epidemiology and Management Challenges in Prolactinomas

Clinically relevant pituitary adenomas are present in about 1 per 1,000 of the general population and prolactinomas are by far the most common clinical subtype of pituitary adenomas. Usually prolactinomas affect premenopausal women and present with typical symptoms of menstrual disturbance and/or galactorrhea. They are generally managed with dopamine agonists to restore fertility and to control symptoms and tumor size. In a subset of prolactinomas, however, management remains challenging. Studies in recent years have identified the factors related to dopamine agonist resistance, such as male sex, genetic features, and aggressive tumor behavior. Certain other patient groups represent particular challenges for management, such as pediatric patients and pregnant women. Treatment with dopamine agonists is usually safe and effective, and adverse effects such as clinically relevant cardiac valvular complications and impulse control disorders may occur in isolated instances. A number of important disease characteristics of prolactinomas remain to be explained, such as the difference in sex prevalence before and after menopause, the higher prevalence of macroadenomas in older males, and the biochemical mechanisms of resistance to dopaminergic agonists.

Screening for valve disease in patients with hyperprolactinaemia disorders prescribed cabergoline: a service evaluation and literature review

OBJECTIVES

The indication for screening for valvular heart disease in patients taking cabergoline is based on evidence from patients with Parkinson's disease on high-dose medication. However, current patients take much lower doses for indications such as hyperprolactinaemia disorders. Contemporary guidelines for echocardiogram monitoring in patients taking cabergoline are conflicting. This study aimed to review current clinical practice in our area regarding echocardiographic screening and to review the literature examining the evidence of valvular heart disease in patients taking lower dose cabergoline.

METHODS

This was a retrospective study of all patients with hyperprolactinaemia disorders prescribed cabergoline in a single UK NHS health board between January 2014 and July 2015. The proportion of patients receiving baseline and follow-up echocardiograms was recorded. A review of the published literature was carried out using the databases EMBASE and Medline to examine the current evidence for the effect cabergoline has on cardiac valves in patients treated for hyperprolactinaemia disorders.

RESULTS

The mean age was 51.7 ± 16.5 years with a 64.4% female predominance. The mean duration of therapy was 5.9 years ± 4.1 years. Of the total cohort (n = 45), two (4.4%) patients had an initial baseline echocardiogram and five (13.2%) had follow-up echocardiograms every 24 months. Of the 25 articles identified, 12 showed no clinically significant evidence of valvular dysfunction in the cabergoline group groups. Of the remaining 13 articles, evidence for valvular changes was confined to high cumulative dose cabergoline patients and there was only one confirmed case of 'cabergoline associated valvulopathy' described.

CONCLUSIONS

Clinically significant valvular dysfunction is uncommon and generally only reported in high cumulative dose treatment groups. We propose that clearer national guidelines are required and that echocardiogram screening be reserved for patients who are high risk, are taking a high weekly dose (≥2 mg cabergoline weekly) or high cumulative dose.

Cabergoline in acromegaly

Acromegaly, a rare disease due to growth hormone (GH) hypersecretion by a pituitary adenoma, is associated with severe comorbidity and premature death if not adequately treated. The usual first-line treatment is surgery. Various drugs, including somatostatin receptor ligands, dopamine agonists and GH receptor antagonists, are now available for use if surgery fails to suppress GH/IGF-I hypersecretion. Cabergoline, now the preferred dopamine agonist for treating hyperprolactinemia, is also used off-label for treating acromegaly. Cabergoline monotherapy is reported to normalize IGF-I levels in more than one-third of patients with acromegaly. When a somatostatin receptor ligand proves ineffective, cabergoline add-on therapy normalizes the IGF-I level in 40-50% of patients. Finally, when combined with the GH receptor antagonist pegvisomant in patients with mild uncontrolled disease, cabergoline helps to achieve normal IGF-I levels while avoiding the need for high-dose pegvisomant. Cabergoline is also inexpensive and well tolerated; in particular, it does not appear to promote heart valve disease.

The role of combination medical therapy in the treatment of acromegaly

PURPOSE

Uncontrolled acromegaly results in approximately 2-fold excess mortality. Pituitary surgery is first-line therapy, and medical treatment is indicated for persistent disease. While cabergoline and pegvisomant are used in select patients, somatostatin receptor ligands (SRLs) remain the cornerstone of medical treatment. Management of patients poorly responsive to SRLs is therefore, challenging. The purpose of this review is to highlight the options for combination medical therapy in the treatment of acromegaly, with an emphasis on efficacy and safety.

METHODS

All original articles/abstracts detailing combination medical therapy in acromegaly were identified from a PubMed search.

RESULTS

Studies reviewed included retrospective and open-label prospective studies. While the combination of SRL and cabergoline was generally well tolerated, a lower baseline insulin-like growth factor-1 (IGF-1) level was the best predictor of efficacy; this combination may be most effective in patients with mildly elevated IGF-1. SRL-pegvisomant combination normalized IGF-1 in the majority of patients; continued efficacy despite individual drug dosing reduction was also reported. The risk of significant liver enzyme elevation was, however, higher than that reported with SRL monotherapy; close monitoring is recommended. Data on pegvisomant-cabergoline combination is limited, but this may be an option in the setting of SRL intolerance. Reports on temozolomide used in combination with other medical therapies in patients with aggressive GH-secreting tumors are also summarized.

CONCLUSION

While more prospective, randomized controlled trials on long-term efficacy and safety are needed, combination medical therapy remains a treatment strategy that should be considered for acromegaly patients poorly responsive to SRLs.

Long-term cardiac (valvulopathy) safety of cabergoline in prolactinoma

BACKGROUND

Clinical relevance of association of cabergoline use for hyperprolactinemia and cardiac valvulopathy remains unclear.

OBJECTIVE

The aim of the study was to determine the prevalence of valvular heart abnormalities in patients taking cabergoline for the treatment of prolactinoma and to explore any associations with the cumulative dose of drug used.

DESIGN

A cross-sectional echocardiographic study was performed in patients who were receiving cabergoline therapy for prolactinoma.

RESULTS

Hundred (61 females, 39 males) prolactinoma cases (81 macroprolactinoma and 19 microprolactinoma) were included in the study. The mean age at presentation was 33.9 ± 9.0 years (range: 16-58 years). The mean duration of treatment was 53.11 ± 43.15 months (range: 12-155 months). The mean cumulative dose was 308.6 ± 290.2 mg (range: 26-1196 mg; interquartile range: 104-416 mg). Mild mitral regurgitation was present in one patient (cumulative cabergoline dose 104 mg). Mild tricuspid regurgitation was present in another two patients (cumulative cabergoline dose 52 mg and 104 mg). Aortic and pulmonary valve functioning was normal in all the cases. There were no cases of significant valvular regurgitation (moderate to severe, Grade 3-4). None of the patients had morphological abnormalities such as thickening, calcification, and restricted mobility of any of the cardiac valves.

CONCLUSION

Cabergoline appears to be safe in patients with prolactinoma up to the cumulative dose of ~300 mg. The screening for valvulopathy should be restricted to those with higher cumulative cabergoline exposure.

Prospective, long-term study of the effect of cabergoline on valvular status in patients with prolactinoma and idiopathic hyperprolactinemia

Since the 1990's cabergoline has been the treatment of choice in prolactinoma, as it permits rapid and effective hormonal and tumor control in most cases. Evidence of cardiac valvulopathy was demonstrated in Parkinson's disease patients treated with dopamine agonists. Retrospective studies in prolactinoma patients treated with cabergoline at lower doses did not show such an effect. However, few prospective data with long-term follow-up are available. The aim of this study was to assess the safety of cabergoline regarding cardiac valvular status during prospective follow-up in patients treated for prolactinoma or idiopathic hyperprolactinemia. We report here a series of 100 patients (71F; median age at diagnosis: 41.5 years) treated with cabergoline for endocrine diseases (prolactinoma n = 89, idiopathic hyperprolactinemia n = 11). All patients underwent complete transthoracic echocardiographic studies at baseline and during long-term prospective surveillance using the same equipment and performed by the same technicians. The median interval between baseline and last follow-up echocardiographic studies while on cabergoline was 62.5 months (interquartile range: 34.75-77.0). The median total duration of cabergoline treatment was 124.5 months (interquartile range: 80.75-188.75) and the median cumulative total dose of cabergoline was 277.8 mg (interquartile range : 121.4-437.8 mg) at last follow-up. We found no clinically relevant alterations in cardiac valve function or valvular calcifications with cabergoline treatment. Our data suggest that findings from retrospective analyses are correct and that cabergoline is a safe chronic treatment at the doses used typically in endocrinology.

A Follow-Up Study of the Prevalence of Valvular Heart Abnormalities in Hyperprolactinemic Patients Treated With Cabergoline

CONTEXT

Uncertainty exists whether the long-term use of ergot-derived dopamine agonist (DA) drugs for the treatment of hyperprolactinemia may be associated with clinically significant valvular heart disease and whether current regulatory authority guidelines for echocardiographic screening are clinically appropriate.

OBJECTIVE

Our objective was to provide follow-up echocardiographic data on a previously described cohort of patients treated with DA for lactotrope pituitary tumors and to explore possible associations between structural and functional valve abnormalities with the cumulative dose of drug used.

DESIGN

Follow-up echocardiographic data were collected from a proportion of our previously reported cohort of patients; all had received continuous DA therapy for at least 2 years in the intervening period. Studies were performed according to British Society of Echocardiography minimum standards for adult transthoracic echocardiography. Generalized estimating equations with backward selection were used to determine odds ratios of valvular heart abnormalities according to tertiles of cumulative cabergoline dose, using the lowest tertile as the reference group.

SETTING

Thirteen centers of secondary/tertiary endocrine care across the United Kingdom were included.

RESULTS

There were 192 patients (81 males; median age, 51 years; interquartile range [IQR], 42-62). Median (IQR) cumulative cabergoline doses at the first and second echocardiograms were 97 mg (20-377) and 232 mg (91-551), respectively. Median (IQR) duration of uninterrupted cabergoline therapy between echocardiograms was 34 months (24-42). No associations were observed between cumulative doses of dopamine agonist used and the age-corrected prevalence of any valvular abnormality.

CONCLUSION

This large UK follow-up study does not support a clinically significant association between the use of DA for the treatment of hyperprolactinemia and cardiac valvulopathy.

Long-term outcome of macroprolactinomas

OBJECTIVE

Management of macroprolactinomas has dramatically changed in recent decades, from surgical to medical treatment as first-line therapy, with the development of dopamine agonists (DA). But few data exist on the long-term outcome of these patients.

PATIENTS AND METHODS

Retrospective descriptive multicenter study of patients with macroprolactinoma followed for at least 5 years between 1973 and 2008 at the University Hospitals of Strasbourg and Marseille.

RESULTS

Forty-eight patients were included with 27 men, hypopituitarism in 33.3% of all patients and mean serum prolactin (PRL) level at diagnosis 2218.2±4154.7μg/L. Among the patients, 58.3% received medical treatment, 25% had additional surgery and 12.5% surgery and radiotherapy. The mean follow-up duration was 196±100 months. At the end of follow-up, 10 patients (20.8%) were cured (i.e. normal PRL level and normal imaging, no symptoms and withdrawal of DA≥1 year), 33 (68.8%) were controlled (i.e. normal PRL level, normal or abnormal imaging, no symptoms, DA in progress) and 5 (10.4%) were uncontrolled. Uncontrolled patients had significant higher baseline PRL level (P=0.0412) and cabergoline cumulative dose (P=0.0065) compared to the controlled group. There was no increase in frequency of hypopituitarism. Clinically significant valvular heart disease was found in 2 patients but screening was not systematic.

CONCLUSIONS

Macroprolactinoma is currently most often a chronic disease controlled with DA. However, uncertainty about the adverse effects associated with high cumulative doses and the lack of data on the prognosis at very long-term should incite to revisit current strategies, including the role of surgery combined to medical treatment.

The need for annual echocardiography to detect cabergoline-associated valvulopathy in patients with prolactinoma: a systematic review and additional clinical data

Present recommendations by the US Food and Drug Administration advise that patients with prolactinoma treated with cabergoline should have an annual echocardiogram to screen for valvular heart disease. Here, we present new clinical data and a systematic review of the scientific literature showing that the prevalence of cabergoline-associated valvulopathy is very low. We prospectively assessed 40 patients with prolactinoma taking cabergoline. Cardiovascular examination before echocardiography detected an audible systolic murmur in 10% of cases (all were functional murmurs), and no clinically significant valvular lesion was shown on echocardiogram in the 90% of patients without a murmur. Our systematic review identified 21 studies that assessed the presence of valvular abnormalities in patients with prolactinoma treated with cabergoline. Including our new clinical data, only two (0·11%) of 1811 patients were confirmed to have cabergoline-associated valvulopathy (three [0·17%] if possible cases were included). The probability of clinically significant valvular heart disease is low in the absence of a murmur. On the basis of these findings, we challenge the present recommendations to do routine echocardiography in all patients taking cabergoline for prolactinoma every 12 months. We propose that such patients should be screened by a clinical cardiovascular examination and that echocardiogram should be reserved for those patients with an audible murmur, those treated for more than 5 years at a dose of more than 3 mg per week, or those who maintain cabergoline treatment after the age of 50 years.

Drug-induced retroperitoneal fibrosis: short aetiopathogenetic note, from the past times of ergot-derivatives large use to currently applied bio-pharmacology

Among the secondary forms of retroperitoneal fibrosis (RPF), that drug-induced shows very intriguing aspects given both the broad range of involved pharmaceuticals and the considerable interest arisen from the related pathogenetic mechanisms. The particular incidence, in the last four decades past century, of the RPF due to long-term use of ergot alkaloid derivatives (ergotamine, methysergide, pergolide, bromocriptine, cabergoline) and specific L-dopa derived agents, such as methyldopa, as well as to different analgesics, came progressively down given that their long-term use for either the prevention of migraine attacks or the therapy of chronic pathologies (Parkinson's disease, prolactinoma, pain management, etc) has been, year after year, supplanted or even made unavailable in many countries. More recently, instead, the occurrence of the RPF has been sometimes identified with the use of antitumoral chemotherapeutics, such as carboplatin and methotrexate, and, just lately, as an unusual side-effect of certain biological agents, about which it is timely to go into specific pathogenetic problems in more depth.

Cabergoline use for pituitary tumors and valvular disorders

Cabergoline (CAB) is widely used for the medical treatment of pituitary tumors, particularly those associated with hormone hypersecretion. Whether treatment with CAB is associated with an increased risk of clinically relevant cardiac valve disease in patients with pituitary tumors is still debated. In most studies, CAB has been found not associated with an increased risk of significant valvulopathy, and no correlation has been shown between valvular abnormalities and CAB duration or cumulative dose. This review provides an overview of the studies reporting on the outcome of CAB in terms of cardiac valve disease in patients with pituitary tumors.

Challenges and controversies in the treatment of prolactinomas

Recent studies have reported a higher prevalence of pituitary tumors than previously thought. Among these tumors, prolactinomas occur in up to 66% of cases. Since the mid-1980s, the widespread use of dopamine agonists has facilitated the management of the majority of prolactinomas, allowing biological and tumoral control in most cases. The less frequent cases of resistant prolactinomas remain challenging despite a multimodal therapy approach. The understanding of genetic alterations in familial and aggressive pituitary tumors provides new perspectives in the management of some prolactinomas. Genetic screening should be considered, particularly in familial cases but also in young patients with macroprolactinomas, as some mutations can predict potential aggressiveness.

A cross-sectional study of the prevalence of cardiac valvular abnormalities in hyperprolactinemic patients treated with ergot-derived dopamine agonists

CONTEXT

Concern exists in the literature that the long-term use of ergot-derived dopamine agonist drugs for the treatment of hyperprolactinemia may be associated with clinically significant valvular heart disease.

OBJECTIVE

The aim of the study was to determine the prevalence of valvular heart abnormalities in patients taking dopamine agonists as treatment for lactotrope pituitary tumors and to explore any associations with the cumulative dose of drug used.

DESIGN

A cross-sectional echocardiographic study was performed in a large group of patients who were receiving dopamine agonist therapy for hyperprolactinemia. Studies were performed in accordance with the British Society of Echocardiography minimum dataset for a standard adult transthoracic echocardiogram. Poisson regression was used to calculate relative risks according to quartiles of dopamine agonist cumulative dose using the lowest cumulative dose quartile as the reference group.

SETTING

Twenty-eight centers of secondary/tertiary endocrine care across the United Kingdom participated in the study.

RESULTS

Data from 747 patients (251 males; median age, 42 y; interquartile range [IQR], 34-52 y) were collected. A total of 601 patients had taken cabergoline alone; 36 had been treated with bromocriptine alone; and 110 had received both drugs at some stage. The median cumulative dose for cabergoline was 152 mg (IQR, 50-348 mg), and for bromocriptine it was 7815 mg (IQR, 1764-20 477 mg). A total of 28 cases of moderate valvular stenosis or regurgitation were observed in 24 (3.2%) patients. No associations were observed between cumulative doses of dopamine agonist used and the age-corrected prevalence of any valvular abnormality.

CONCLUSION

This large UK cross-sectional study does not support a clinically concerning association between the use of dopamine agonists for the treatment of hyperprolactinemia and cardiac valvulopathy.

Kinetics of 5-HT2B receptor signaling: profound agonist-dependent effects on signaling onset and duration

The kinetics of drug-receptor interactions can profoundly influence in vivo and in vitro pharmacology. In vitro, the potencies of slowly associating agonists may be underestimated in assays capturing transient signaling events. When divergent receptor-mediated signaling pathways are evaluated using combinations of equilibrium and transient assays, potency differences driven by kinetics may be erroneously interpreted as biased signaling. In vivo, drugs with slow dissociation rates may display prolonged physiologic effects inconsistent with their pharmacokinetic profiles. We evaluated a panel of 5-hydroxytryptamine2B (5-HT2B) receptor agonists in kinetic radioligand binding assays and in transient, calcium flux assays, and inositol phosphate accumulation assays; two functional readouts emanating from Gαq-mediated activation of phospholipase C. In binding studies, ergot derivatives demonstrated slow receptor association and dissociation rates, resulting in significantly reduced potency in calcium assays relative to inositol phosphate accumulation assays. Ergot potencies for activation of extracellular signal-regulated kinases 1 and 2 were also highly time-dependent. A number of ergots produced wash-resistant 5-HT2B signaling that persisted for many hours without appreciable loss of potency, which was not explained simply by slow receptor-dissociation kinetics. Mechanistic studies indicated that persistent signaling originated from internalized or sequestered receptors. This study provides a mechanistic basis for the long durations of action in vivo and wash-resistant effects in ex vivo tissue models often observed for ergots. The 5-HT2B agonist activity of a number of ergot-derived therapeutics has been implicated in development of cardiac valvulopathy in man. The novel, sustained nature of ergot signaling reported here may represent an additional mechanism contributing to the valvulopathic potential of these compounds.

A consensus on the diagnosis and treatment of acromegaly complications

In March 2011, the Acromegaly Consensus Group met to revise and update the guidelines on the diagnosis and treatment of acromegaly complications. The meeting was sponsored by the Pituitary Society and the European Neuroendocrinology Association and included experts skilled in the management of acromegaly. Complications considered included cardiovascular, endocrine and metabolic, sleep apnea, bone diseases, and mortality. Outcomes in selected, related clinical conditions were also considered, and included pregnancy, familial acromegaly and invasive macroadenomas. The need for a new disease staging model was considered, and design of such a tool was proposed.

Transforming growth factor β1 is not a reliable biomarker for valvular fibrosis but could be a potential serum marker for invasiveness of prolactinomas (pilot study)

BACKGROUND

Transforming growth factor β1 (TGFβ1) signaling pathway is crucial for both human fibrogenesis and tumorigenesis.

OBJECTIVE

This study aimed to investigate the usefulness of TGFβ1 and matrix metalloproteinase 2 (MMP2) as potential circulating markers for fibrotic valvular heart disease (FVHD) and invasiveness as well as of Fetuin A as a marker for calcification in patients with prolactinomas.

DESIGN

The study population consisted of 147 subjects divided into four groups: 30 dopamine agonist (DA)-treated prolactinoma patients with proven FVHD and three control groups with normal echocardiograms: 43 DA-treated patients, 26 naïve patients, and 48 healthy subjects.

RESULTS

We observed significantly higher serum TGFβ1 levels in all three patient groups than in the healthy subjects (21.4 ± 8.86 vs 19.1 ± 9.03 vs 20.7±11.5 vs 15.8 ± 7.2 ng/ml; P=0.032). Moreover, TGFβ1 levels were significantly higher in patients with macroprolactinomas and invasive prolactinomas than in those with microprolactinomas and noninvasive tumors respectively. In addition, a strong positive linear relationship between TGFβ1 levels and invasiveness score (ρ=0.924; P<0.001) and a moderate correlation between TGFβ1 levels and tumor volume (r=0.546; P<0.002) were observed in patients with invasive prolactinomas. By contrast, prolactin (PRL) levels exhibited a better correlation with tumor volume (r=0.721; P<0.001) than with invasiveness score (ρ=0.436; P<0.020). No significant difference was observed in Fetuin A levels between patients with FVHD and healthy controls. Results concerning MMP2 were unclear.

CONCLUSIONS

TGFβ1, MMP2, and Fetuin A are not reliable biomarkers for valvular fibrosis and calcification in DA-treated patients with prolactinomas, but TGFβ1 may represent a useful serum marker for tumor invasiveness. The simultaneous determination of TGFβ1 and PRL levels could improve the noninvasive assessment of prolactinoma behavior.

Treatment of hyperprolactinemia: a systematic review and meta-analysis

BACKGROUND

Hyperprolactinemia is a common endocrine disorder that can be associated with significant morbidity. We conducted a systematic review and meta-analyses of outcomes of hyperprolactinemic patients, including microadenomas and macroadenomas, to provide evidence-based recommendations for practitioners. Through this review, we aimed to compare efficacy and adverse effects of medications, surgery and radiotherapy in the treatment of hyperprolactinemia.

METHODS

We searched electronic databases, reviewed bibliographies of included articles, and contacted experts in the field. Eligible studies provided longitudinal follow-up of patients with hyperprolactinemia and evaluated outcomes of interest. We collected descriptive, quality and outcome data (tumor growth, visual field defects, infertility, sexual dysfunction, amenorrhea/oligomenorrhea and prolactin levels).

RESULTS

After review, 8 randomized and 178 nonrandomized studies (over 3,000 patients) met inclusion criteria. Compared to no treatment, dopamine agonists significantly reduced prolactin level (weighted mean difference, -45; 95% confidence interval, -77 to -11) and the likelihood of persistent hyperprolactinemia (relative risk, 0.90; 95% confidence interval, 0.81 to 0.99). Cabergoline was more effective than bromocriptine in reducing persistent hyperprolactinemia, amenorrhea/oligomenorrhea, and galactorrhea. A large body of noncomparative literature showed dopamine agonists improved other patient-important outcomes. Low-to-moderate quality evidence supports improved outcomes with surgery and radiotherapy compared to no treatment in patients who were resistant to or intolerant of dopamine agonists.

CONCLUSION

Our results provide evidence to support the use of dopamine agonists in reducing prolactin levels and persistent hyperprolactinemia, with cabergoline proving more efficacious than bromocriptine. Radiotherapy and surgery are useful in patients with resistance or intolerance to dopamine agonists.

Increased prevalence of subclinical cardiac valve fibrosis in patients with prolactinomas on long-term bromocriptine and cabergoline treatment

BACKGROUND

In contrast to cabergoline, evidence-based information about a possible profibrotic effect of bromocriptine in prolactinoma patients is extremely limited.

OBJECTIVE

To assess the prevalence of valvular lesions among patients on long-term bromocriptine or cabergoline therapy.

DESIGN

Case-control study.

METHODS

A transthoracic echocardiographic evaluation was performed in 334 subjects divided into four groups: 103 cabergoline treated, 55 bromocriptine treated, 74 naïve patients, and 102 controls.

RESULTS

Clinically relevant valve regurgitations were equally prevalent in all investigated groups whereas subclinical valve fibrosis was significantly more frequent in both bromocriptine- and cabergoline-treated patients (40 vs 43.6 vs 21.6 vs 23.5%; P=0.004). The odds ratio (OR) for developing valvular fibrosis was 2.27 (95% CI 1.17-4.41; P=0.016) for cabergoline and 2.66 (95% CI 1.22-5.78; P=0.014) for bromocriptine groups compared with subjects not exposed to dopamine agonists (DAs). A significantly higher pulmonary arterial pressure corresponding to the longer treatment duration was observed among patients taking bromocriptine compared with cabergoline-treated subjects.

CONCLUSIONS

Long-term treatment with cabergoline and bromocriptine seems not to be associated with an increased risk of clinically significant valve disease but possible subclinical lesions should be expected. An echocardiographic examination is recommended at the beginning and periodically during therapy with DAs acting as full or partial agonists of 5-hydroxytrytamine 2B receptors (cabergoline and bromocriptine). Bromocriptine seems not to be a safe alternative for patients receiving cabergoline treatment who have preexisting or diagnosed abnormalities suggesting valvular, interstitial myocardial, or pulmonary fibrosis. Further studies are needed to investigate the possible impact of DA treatment on pulmonary arterial pressure.

2012 update in the treatment of prolactinomas

New information has been provided over the last years regarding treatment of prolactinomas and will be reviewed in this update. Medical treatment with a dopamine agonist (DA) remains the cornerstone of therapy and cabergoline is the first choice, due to its high efficacy and good tolerability profile. Prolonged remission after discontinuation of DA may be observed if treatment has been given for at least two years, normal prolactin has been obtained with a low dose and tumoral diameter has been reduced by at least 50%. Although the risk of restrictive cardiac valve disease is low at the standard doses of cabergoline used for the treatment of hyperprolactinaemia, long-term echocardiographic surveillance is however indicated, in particular in resistant patients who need higher doses of cabergoline (2.0 mg/week or more). Neurosurgical treatment of prolactinomas is less effective than medical therapy and recurrence of hyperprolactinaemia is frequent. Besides classical indications such as drug intolerance, resistance or acute complications, new indications have emerged such as young patients with a high likelihood of complete tumour resection and who do not wish to take prolonged medical treatment, or patients who require high doses of cabergoline, in whom surgical debulking may significantly improve postoperative hormonal control. Finally, recent data indicate that cabergoline is safe for the developing foetus and for the mother, and therefore should not be preventively withdrawn in a young woman wishing to become pregnant.

Medical treatment of prolactinomas

Prolactinomas, the most prevalent type of neuroendocrine disease, account for approximately 40% of all pituitary adenomas. The most important clinical problems associated with prolactinomas are hypogonadism, infertility and hyposexuality. In patients with macroprolactinomas, mass effects, including visual field defects, headaches and neurological disturbances, can also occur. The objectives of therapy are normalization of prolactin levels, to restore eugonadism, and reduction of tumor mass, both of which can be achieved in the majority of patients by treatment with dopamine agonists. Given their association with minimal morbidity, these drugs currently represent the mainstay of treatment for prolactinomas. Novel data indicate that these agents can be successfully withdrawn in a subset of patients after normalization of prolactin levels and tumor disappearance, which suggests the possibility that medical therapy may not be required throughout life. Nevertheless, multimodal therapy that involves surgery, radiotherapy or both may be necessary in some cases, such as patients who are resistant to the effects of dopamine agonists or for those with atypical prolactinomas. This Review reports on efficacy and safety of pharmacotherapy in patients with prolactinomas.

Effect of dopaminergic drug treatment on surgical findings in prolactinomas

It has been reported that prolactinomas treated with Bromocriptine (BROM) show fibrosis that may interfere with complete surgical resection. The same has not been reported for Cabergoline (CAB). We retrospectively studied 24 consecutive patients (13 females, mean age 40 years, range 16-60) with histopathologically confirmed prolactinomas undergoing surgical resection at Johns Hopkins Hospital between 1992 and 2009. We compared these prolactinomas to 34 patients (22 females, mean age 42.9 years, range 15-75) with GH-secreting adenoma. The operative notes from 7 different neurosurgeons were reviewed to catalog the tumors as fibrous or not fibrous. Of the 24 prolactinomas, 21 (87.5%) were previously treated with DA. Indication for surgery was: DA resistance (n.5), DA intolerance (n.6), persistent mass effect (n.7) and CSF leak (n.3). Five (14.7%) of GH-secreting adenomas, were exposed to DA and/or somatostatin analogs. We found that 54% of prolactinomas and only 6% of GH-secreting adenomas were described as fibrous. 10/12 (77%) of prolactinomas exposed to BROM for at least 1 month, 2/9 (22%) exposed to CAB only, and 1/3 (33%) not previously treated were fibrous (P < 0.05). The mean BROM cumulative dose was 406 mg (range 75-1,375), while CAB dose was 28 mg (range 6-70). Only 18% of non-fibrous prolactinomas had been exposed to BROM. Only 3 patients had persistent biochemical remission (2 treated with CAB and 1 not treated). Patients exposed to BROM for at least 1 month are more likely to have tumor fibrosis than patients that are untreated or treated with CAB.