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Neuroendocrinology 2022Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of... (Review)
Review
Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of cabergoline-treated individuals exhibit resistance to DAs. In addition, the mechanism underlying this phenomenon remains elusive. In this study, we summarize the major findings regarding the role of microRNAs (miRNAs) in the pathogenesis of DA-resistant prolactinoma (DARP). Currently available evidence suggests that miRNAs are usually dysregulated in DARP and that, although controversial, the dysregulated miRNAs target the transforming growth factor (TGF)-β, dopamine 2 receptor (D2R), or estradiol (E2)/estrogen receptor (ER) signaling pathways to mediate the therapeutic effect of DAs. These findings provide new incentives for research on innovative strategies for predicting patients' responsiveness to dopamine therapies and for developing treatment approaches. Unfortunately, recent studies tended to focus exclusively on the differential miRNA expression profiles between DARP and dopamine-sensitive prolactinoma, and no definitive consensus has been reached regarding the role of these miRNAs in the modulation mechanism. Therefore, current and future efforts should be directed toward the exploration of the mechanism underlying the dysregulation of miRNAs as well as of the target proteins that are affected by the dysregulated miRNAs. Furthermore, the modulation of the expression of dysregulated miRNAs, which target the D2R, TGF-β, or E2/ER signaling pathways, might be a promising alternative to treat patients with DARP and improve their prognosis.
Topics: Dopamine; Dopamine Agonists; Drug Resistance, Neoplasm; Humans; MicroRNAs; Pituitary Neoplasms; Prolactinoma
PubMed: 34034260
DOI: 10.1159/000517356 -
Cureus Oct 2022Aim Prolactinoma, a prolactin (PRL) secreting functioning pituitary tumor, is the most common of all pituitary adenomas (PA) accounting for 40-60% and dopamine agonists...
Aim Prolactinoma, a prolactin (PRL) secreting functioning pituitary tumor, is the most common of all pituitary adenomas (PA) accounting for 40-60% and dopamine agonists (DA) are the cornerstone of treatment. The aim of this study was to review the clinical presentation, treatment modalities and therapeutic outcomes of patients with prolactinomas in the South Asia region. Methods This retrospective study was conducted in the Endocrinology Department of Shaukat Khanum Memorial Cancer Hospital and Research Centre from December 2011 till December 2019. Medical records were used to retrieve for patient's demographics, clinical features at diagnosis, PRL levels and size of prolactinoma on MRI at diagnosis and after start of dopamine agonists and outcome of medical management. Results A total of 107 patients were included in this study. Mean age at diagnosis was 35 (22-54) years for men and 32 (18-50) years for women and 66.4% (71) of the patients were females. Our study included 38 (35.5%) microadenoma, 50 (46.7%) macroadenoma and 19 (17.8%) giant adenomas. At presentation, the most common symptom among females was menstrual irregularity/amenorrhea seen in 73.2% of females and among males was visual disturbance (80.6%). A significant reduction in PRL levels was seen within six to 12 months of treatment. Mean PRL levels decreased from 3162.8 ng/ml to 1.52 ng/ml. A notable decrease in tumor size was seen with medical management, mean adenoma size decreased from 2.18 cm to 1.04 cm. With cabergoline (CAB) 83.3% biochemical cure was seen compared to bromocriptine (BRC) which has 60.4%. The radiological response rate in CAB and BRC groups was 65.45% and 60%, respectively. Complete resolution of adenoma was seen in 13 patients (nine were microadenoma, two macro and two giant adenomas). The prolactin level at diagnosis was positively correlated with maximum tumor diameter (r = 0.469, P = 0.001). Two patients developed cerebrospinal fluid (CSF) rhinorrhea and the defect was repaired in both patients. Median follow-up duration was 40 (12-288) months. Conclusion Clinical presentation and demographics of prolactinoma are the same in our region when compared to the rest of the world. Cabergoline is superior to bromocriptine in prolactin normalization and tumor shrinkage but still bromocriptine is being used in a significant number of patients in low-income countries as first-line due to its low cost.
PubMed: 36337795
DOI: 10.7759/cureus.29822 -
Journal of Clinical Medicine May 2023Our purpose is to provide new insights concerning the challenges of pituitary apoplexy in pregnancy (PAP) and the postpartum period (PAPP). This is a narrative review of... (Review)
Review
Our purpose is to provide new insights concerning the challenges of pituitary apoplexy in pregnancy (PAP) and the postpartum period (PAPP). This is a narrative review of the English literature using a PubMed search. The inclusion criteria were clinically relevant original studies (January 2012-December 2022). Overall, we included 35 original studies: 7 observational studies (selected cases on PA) and 28 case reports, including 4 case series (N = 49; PAP/PAPP = 43/6). The characteristics of PAP patients (N = 43) are as follows: maternal age between 21 and 41 (mean of 27.76) years; 21/43 subjects with a presentation during the third trimester (only one case during first trimester); average weak of gestation of 26.38; most females were prim gravidae; 19 (out of 30 patients with available data on delivery) underwent a cesarean section. Headache remains the main clinical feature and is potentially associated with a heterogeneous panel (including visual anomalies, nausea, vomiting, cranial nerve palsies, diabetes insipidus, photophobia, and neck stiffness). Pre-pregnancy medication included dopamine agonists (15/43) and terguride (1/43) in addition to subsequent insulin therapy for gestational diabetes (N = 2) and type 1 diabetes mellitus (N = 1). Overall, 29/43 females received the conservative approach, and 22/43 women had trans-sphenoidal surgery (TSS) (and 10/22 had the initial approach). Furthermore, 18/43 patients had a pituitary adenoma undiagnosed before pregnancy. Most PA-associated tumors were prolactinomas (N = 26/43), with the majority of them (N = 16/26) being larger than 1 cm. A maternal-fetal deadly outcome is reported in a single case. The characteristics of PAPP patients (N = 6) are as follows: mean age at diagnosis of 33 years; 3/6 subjects had PA during their second pregnancy; the timing of PA varied between 5 min and 12 days after delivery; headache was the main clinical element; 5/6 had no underlying pituitary adenoma; 5/6 patients were managed conservatively and 1/6 underwent TSS; pituitary function recovered (N = 3) or led to persistent hypopituitarism (N = 3). In conclusion, PAP represents a rare, life-threatening condition. Headache is the most frequent presentation, and its prompt distinction from other conditions associated with headache, such as preeclampsia and meningitis, is essential. The index of suspicion should be high, especially in patients with additional risk factors such as pre-gestation treatment with dopamine agonists, diabetes mellitus, anticoagulation therapy, or large pituitary tumors. The management is conservative in most cases, and it mainly includes corticosteroid substitution and dopamine agonists. The most frequent surgical indication is neuro-ophthalmological deterioration, although the actual risk of pituitary surgery during pregnancy remains unknown. PAPP is exceptionally reported. To our knowledge, this sample-case series study is the largest of its kind that is meant to increase the awareness to the benefit of the maternal-fetal outcomes from multidisciplinary insights.
PubMed: 37240522
DOI: 10.3390/jcm12103416 -
BMC Endocrine Disorders Sep 2020The specific underlying pathogenesis of prolactinoma has not been clarified yet, to the best of our knowledge. p38 mitogen-activated protein kinase (MAPK) signaling...
BACKGROUND
The specific underlying pathogenesis of prolactinoma has not been clarified yet, to the best of our knowledge. p38 mitogen-activated protein kinase (MAPK) signaling including p38α MAPK (MAPK14), p38β (MAPK11), p38γ (MAPK12) and p38δ (MAPK13) is associated with the development and progression of several types of cancer.
METHODS
Immunofluorescence analysis was performed on the prolactin (PRL) and MAPK14 expressions of pituitary gland in C57BL/6 mice and human prolactinoma specimen. In the present study, the role of MAPK14 in prolactinoma was determined using estradiol-induced mice and dopamine D2 receptor knockout (DRD2) mice models in C57BL/6 wild-type (WT), MAPK14 and DRD2MAPK14 mice. GH3 cells were transfected with different sets of MAPK14 small interfering RNA, which to study MAPK14 and PRL expression in GH3 cells.
RESULTS
Immunofluorescence analysis showed that PRL and MAPK14 expression were colocalized and increased in the pituitary gland of mice and human prolactinoma specimen compared with the control specimen. It was shown that PRL and MAPK14 expression was colocalized and increased significantly in the pituitary gland of estradiol-injected prolactinoma mice compared with the control mice. Knockout of MAPK14 significantly inhibited tumor overgrowth, and PRL expression was decreased in estradiol-induced mice. Furthermore, MAPK14 knockout of DRD2MAPK14 mice significantly reduced the overgrowth of pituitary gland and PRL production and secretion compared with DRD2 mice. MAPK14 knockout using siRNA inhibited PRL production in GH3 cells.
CONCLUSION
These results suggest that MAPK14 serves a promoting role in the formation of prolactinoma, and highlights the potential of MAPK14 as a potential therapeutic target in the treatment of prolactinoma.
Topics: Animals; Cell Proliferation; Cells, Cultured; Female; Gene Deletion; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitogen-Activated Protein Kinase 14; Pituitary Neoplasms; Prolactin; Prolactinoma; RNA, Small Interfering; Rats; Receptors, Dopamine D2; Signal Transduction; Somatotrophs
PubMed: 32894113
DOI: 10.1186/s12902-020-00619-z -
International Journal of Molecular... Jul 2021Reproductive function depends upon an operational hypothalamo-pituitary-gonadal (HPG) axis. Due to its role in determining survival versus reproductive strategies, the... (Review)
Review
Reproductive function depends upon an operational hypothalamo-pituitary-gonadal (HPG) axis. Due to its role in determining survival versus reproductive strategies, the HPG axis is vulnerable to a diverse plethora of signals that ultimately manifest with Central Hypogonadism (CH) in all its many guises. Acquired CH can result from any pituitary or hypothalamic lesion, including its treatment (such as surgical resection and/or radiotherapy). The HPG axis is particularly sensitive to the suppressive effects of hyperprolactinaemia that can occur for many reasons, including prolactinomas, and as a side effect of certain drug therapies. Physiologically, prolactin (combined with the suppressive effects of autonomic neural signals from suckling) plays a key role in suppressing the gonadal axis and establishing temporary CH during lactation. Leptin is a further key endocrine regulator of the HPG axis. During starvation, hypoleptinaemia (from diminished fat stores) results in activation of hypothalamic agouti-related peptide neurons that have a dual purpose to enhance appetite (important for survival) and concomitantly suppresses GnRH neurons via effects on neural kisspeptin release. Obesity is associated with hyperleptinaemia and leptin resistance that may also suppress the HPG axis. The suppressibility of the HPG axis also leaves it vulnerable to the effects of external signals that include morphine, anabolic-androgenic steroids, physical trauma and stress, all of which are relatively common causes of CH. Finally, the HPG axis is susceptible to congenital malformations, with reports of mutations within >50 genes that manifest with congenital CH, including Kallmann Syndrome associated with hyposmia or anosmia (reduction or loss of the sense of smell due to the closely associated migration of GnRH with olfactory neurons during embryogenesis). Analogous to the HPG axis itself, patients with CH are often vulnerable, and their clinical management requires both sensitivity and empathy.
Topics: Animals; Gonads; Humans; Hypothalamo-Hypophyseal System; Kallmann Syndrome; Leptin; Prolactin
PubMed: 34360982
DOI: 10.3390/ijms22158217 -
Frontiers in Endocrinology 2021Prolactinoma is the most common type of pituitary tumors, and its resultant tumor occupying and hormone disturbance greatly damage the health of patients. In this study,...
BACKGROUND
Prolactinoma is the most common type of pituitary tumors, and its resultant tumor occupying and hormone disturbance greatly damage the health of patients. In this study, we investigated a protein kinase-PDZ Binding Kinase (PBK)/T-LAK Cell-Originated Protein Kinase (TOPK) as a candidate protein regulating prolactin (PRL) secretion and tumor growth of prolactinomas.
METHODS
Downloaded prolactinoma transcriptome dataset from Gene Expression Omnibus (GEO) database, and screened differentially expressed genes (DEGs) between normal pituitary tissues and prolactinoma tissues. Then, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed, a protein-protein interaction (PPI) network was constructed and the hub genes were identified. After a literature search, TOPK was presumed as an candidate target regulating the prolactinoma. We found a specific inhibitor of TOPK to investigate its effects on the proliferation, migration, apoptosis and PRL secretion of pituitary tumor cells. Finally, the regulation of TOPK inhibitor on its downstream target-p38 Mitogen Activated Protein Kinase (p38 MAPK) was detected to explore the potential mechanism.
RESULTS
A total of 361 DEGs were identified, and 20 hub genes were screened out. TOPK inhibitor HI-TOPK-032 could suppress the proliferation & migration and induce apoptosis of pituitary tumor cells , and reduce PRL secretion and tumor growth . HI-TOPK-032 also inhibited the phosphorylation level of the downstream target p38 MAPK, suggesting that TOPK inhibitors regulate the development of prolactinoma by mediating p38 MAPK.
CONCLUSION
Our study of identification and functional validation of TOPK suggests that this candidate can be a promising molecular target for prolactinoma treatment.
Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Databases, Genetic; Estrogens; Gene Expression Profiling; Gene Regulatory Networks; Humans; In Vitro Techniques; Indolizines; Mitogen-Activated Protein Kinase Kinases; Molecular Targeted Therapy; Phosphorylation; Pituitary Neoplasms; Prolactin; Prolactinoma; Protein Interaction Maps; Quinoxalines; Rats; p38 Mitogen-Activated Protein Kinases
PubMed: 35126305
DOI: 10.3389/fendo.2021.706909 -
Frontiers in Endocrinology 2022Hyperprolactinemia can be caused by several conditions and its effects on the hypothalamic-pituitary-gonadal axis are understood in more detail. Nevertheless, in recent... (Review)
Review
Hyperprolactinemia can be caused by several conditions and its effects on the hypothalamic-pituitary-gonadal axis are understood in more detail. Nevertheless, in recent decades, other metabolic effects have been studied and data pointed to a potential increased cardiovascular disease (CVD) risk. A recent study showed a decrease in total and LDL- cholesterol only in men with prolactinoma treated with dopamine agonists (DA) supporting the previous results of a population study with increased CVD risk in men harboring prolactinoma. However, other population studies did not find a correlation between prolactin (PRL) levels and CVD risk or mortality. There is also data pointing to an increase in high-density lipoprotein levels, and decreases in triglycerides, carotid-intima-media thickness, C-reactive protein, and homocysteine levels in patients with prolactinoma on DA treatment. PRL was also implicated in endothelial dysfunction in pre and postmenopausal women. Withdrawal of DA resulted in negative changes in vascular parameters and an increase in plasma fibrinogen. It has been shown that PRL levels were positively correlated with blood pressure and inversely correlated with dilatation of the brachial artery and insulin sensitivity, increased homocysteine levels, and elevated D-dimer levels. Regarding possible mechanisms for the association between hyperprolactinemia and CVD risk, they include a possible direct effect of PRL, hypogonadism, and even effects of DA treatment, independently of changes in PRL levels. In conclusion, hyperprolactinemia seems to be associated with impaired endothelial function and DA treatment could improve CVD risk. More studies evaluating CVD risk in hyperprolactinemic patients are important to define a potential indication of treatment beyond hypogonadism.
Topics: Male; Humans; Female; Prolactin; Hyperprolactinemia; Prolactinoma; Cardiovascular Diseases; Carotid Intima-Media Thickness; Dopamine Agonists; Cholesterol, LDL; Pituitary Neoplasms; Hypogonadism; Homocysteine
PubMed: 36704037
DOI: 10.3389/fendo.2022.1018090