Aspirin Mediates Its Antitumoral Effect Through Inhibiting PTTG1 in Pituitary Adenoma

CONTEXT

DNA demethylation and inhibitory effects of aspirin on pituitary cell proliferation have been demonstrated.

OBJECTIVE

Our aim was to clarify the molecular mechanisms behind the aspirin-related effects in pituitary cells.

METHODS

DNA methylome and whole transcriptome profile were investigated in RC-4B/C and GH3 pituitary cell lines upon aspirin treatment. Effects of aspirin and a demethylation agent, decitabine, were further tested in vitro. PTTG1 expression in 41 human PitNET samples and whole genome gene and protein expression data of 76 PitNET and 34 control samples (available in Gene Expression Omnibus) were evaluated.

RESULTS

Aspirin induced global DNA demethylation and consequential transcriptome changes. Overexpression of Tet enzymes and their cofactor Uhrf2 were identified behind the increase of 5-hydroxymethylcytosine (5hmC). Besides cell cycle, proliferation, and migration effects that were validated by functional experiments, aspirin increased Tp53 activity through p53 acetylation and decreased E2f1 activity. Among the p53 controlled genes, Pttg1 and its interacting partners were downregulated upon aspirin treatment by inhibiting Pttg1 promoter activity. 5hmC positively correlated with Tet1-3 and Tp53 expression, and negatively correlated with Pttg1 expression, which was reinforced by the effect of decitabine. Additionally, high overlap (20.15%) was found between aspirin-regulated genes and dysregulated genes in PitNET tissue samples.

CONCLUSION

A novel regulatory network has been revealed, in which aspirin regulated global demethylation, Tp53 activity, and Pttg1 expression along with decreased cell proliferation and migration. 5hmC, a novel tissue biomarker in PitNET, indicated aspirin antitumoral effect in vitro as well. Our findings suggest the potential beneficial effect of aspirin in PitNET.

A háziorvos szerepe az acromegaliás betegek gondozásában, fókuszban a szénhidrát-anyagcsere zavara

Az acromegalia ritka, de klinikailag fontos betegség, amelyet a növekedési hormon és az inzulinszerű növekedési faktor-1 krónikusan magas szintje okoz. Számos tünete és komplikációja lehet, amelyek közül a diabetes mellitus gyakori szövődmény. A növekedési hormon különböző mechanizmusokon keresztül hathat a szénhidrát-anyagcserére és idézhet elő inzulinrezisztenciát. Cikkünkben egy acromegaliás beteg esetét dolgozzuk fel, kiemelve a beteg szénhidrátanyagcsere-eltéréseit, valamint az eset kapcsán ismertetjük az acromegalia kezelésében használt terápiás lehetőségeknek a glükózháztartásra gyakorolt hatását a nemzetközi irodalom áttekintésével. A contrainsularis hatású növekedésihormon-túlprodukció rontja a glükóztoleranciát. Ennek megfelelően a kórosan fokozott növekedésihormon-termelést csökkentő különböző kezelési módok (mint a sebészi vagy radioterápia, illetve a gyógyszeres kezelés bizonyos típusai) hatására javul a szénhidrát-anyagcsere. Ugyanakkor a gyógyszeres terápiás lehetőségek közül az első generációs szomatosztatinreceptor-ligandok az esetek kis részében ronthatják a szénhidrátháztartást, míg a második generációs pazireotid a betegek jelentős részénél hyperglykaemiát okoz. Az acromegaliás beteg kezelése komplex feladat, több diszciplína képviselői (endokrinológus, idegsebész, radioterapeuta, az egyes speciális problémák megoldásában részt vevő orvosok, fogorvosok) végzik, de a kezelés összefogásáért az endokrinológus szakorvos a felelős. Az acromegaliának, illetve a kezelés szövődményeinek, kiemelten a szénhidrátháztartás zavarainak ellátásában a háziorvosnak is fontos szerepe van, ehhez pedig ismernie kell a kezelési módozatok főbb pontjait és potenciális mellékhatásait. Orv Hetil. 2020; 161(40): 1724–1729.

Demethylation Status of Somatic DNA Extracted From Pituitary Neuroendocrine Tumors Indicates Proliferative Behavior

BACKGROUND

Cytosine intermediaries 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), epigenetic hallmarks, have never been investigated in pituitary neuroendocrine tumors (PitNET).

OBJECTIVE

To examine methylation-demethylation status of global deoxyribonucleic acid (DNA) in PitNET tissues and to assess its correlation with clinical and biological parameters.

MATERIALS AND METHODS

Altogether, 57 PitNET and 25 corresponding plasma samples were collected. 5mC and 5hmC were investigated using liquid chromatography-tandem mass spectrometry. Expression of DNA methyltransferase 1 (DNMT1); tet methylcytosine dioxygenase 1 through 3 (TET1-3); and ubiquitin-like, containing PHD and RING finger domains 1 and 2 (UHRF1-2) were measured by reverse transcription-polymerase chain reaction. Levels of 5hmC and UHRF1-2 were explored by immunohistochemistry. Effect of demethylating agent decitabine was tested on pituitary cell lines.

RESULTS

5hmC/5mC ratio was higher in less differentiated PitNET samples. A negative correlation between Ki-67 proliferation index and 5hmC, 5hmC to 5mC ratio were revealed. Higher 5mC was observed in SF-1 + gonadotroph adenomas with a higher Ki-67 index. Expressions of TET2 and TET3 were significantly higher in adenomas with higher proliferation rate. UHRF1 showed gradually increased expression in higher proliferative adenoma samples, and a significant positive correlation was detected between UHRF2 expression and 5hmC level. Decitabine treatment significantly decreased 5mC and increased 5hmC levels in both cell lines, accompanied with decreased cell viability and proliferation.

CONCLUSION

The demethylation process negatively correlated with proliferation rate and the ratio of 5hmC to 5mC was higher in less differentiated adenomas. Therefore, epigenetic markers can be potential biomarkers for PitNET behavior. Altering the epigenome in adenoma cells by decitabine decreased proliferation, suggesting that this treatment might be a novel medical treatment for PitNET.

[Early experience with CyberKnife treatment in case of intra-, suprasellar hypernephroma metastasis]

Among tumours found in the suprasellar region metastases are very rare and the most frequent primary tumours are lung and breast cancer. Data of a patient with clear cell renal carcinoma with intra-suprasellar metastasis will be discussed. As in most of the tumours in the sellar region, the first symptom was visual deterioration with visual field defect. A transsphenoidal debulking of the tumour was performed and the residual tumor was treated by CyberKnife hypofractionated stereotactic radiotherapy. Both our patient's visual acuity and visual field impairment improved after the surgery and CyberKnife treatment. At 6-month after irradiation, MR of the sella showed a complete remission of the tumour. This was the first treatment with CyberKnife in our country in case of a tumour close to the optic chiasm. According to our best knowledge, there are 21 cases in the literature with renal cell carcinoma metastasis in the suprasellar region.

Next-generation sequencing identifies novel mitochondrial variants in pituitary adenomas

PURPOSE

Disrupted mitochondrial functions and genetic variants of mitochondrial DNA (mtDNA) have been observed in different human neoplasms. Next-generation sequencing (NGS) can be used to detect even low heteroplasmy-level mtDNA variants. We aimed to investigate the mitochondrial genome in pituitary adenomas by NGS.

METHODS

We analysed 11 growth hormone producing and 33 non-functioning [22 gonadotroph and 11 hormone immunonegative] pituitary adenomas using VariantPro™ Mitochondrion Panel on Illumina MiSeq instrument. Revised Cambridge Reference Sequence (rCRS) of the mtDNA was used as reference. Heteroplasmy was determined using a 3% cutoff.

RESULTS

496 variants were identified in pituitary adenomas with overall low level of heteroplasmy (7.22%). On average, 35 variants were detected per sample. Samples harbouring the highest number of variants had the highest Ki-67 indices independently of histological subtypes. We identified eight variants (A11251G, T4216C, T16126C, C15452A, T14798C, A188G, G185A, and T16093C) with different prevalences among different histological groups. T16189C was found in 40% of non-recurrent adenomas, while it was not present in the recurrent ones. T14798C and T4216C were confirmed by Sanger sequencing in all 44 samples. 100% concordance was found between NGS and Sanger method.

CONCLUSIONS

NGS is a reliable method for investigating mitochondrial genome and heteroplasmy in pituitary adenomas. Out of the 496 detected variants, 414 have not been previously reported in pituitary adenoma. The high number of mtDNA variants may contribute to adenoma genesis, and some variants (i.e., T16189C) might associate with benign behaviour.

Comprehensive analysis of circulating microRNAs in plasma of patients with pituitary adenomas

BACKGROUND

Circulating miRNAs in pituitary adenoma would help patient care especially in non-functioning adenoma cases as minimally invasive biomarkers of tumor recurrence and progression.

AIM

Our aim was to investigate plasma miRNA profile in patients with pituitary adenoma.

MATERIALS AND METHODS

149 plasma and extracellular vesicle (preoperative, early- and late postoperative) samples were collected from 45 pituitary adenoma patients. Adenomas were characterized based on anterior pituitary hormones and transcription factors by immunostaining. MiRNA next generation sequencing was performed on 36 samples (discovery set). Individual TaqMan assay was used for validation on extended sample set. PA tissue miRNAs were evaluated by TaqMan array and literature data.

RESULTS

Global downregulation of miRNA expression was observed in plasma samples of pituitary adenoma patients compared to normal samples. Expression of 29 miRNAs and isomiR variants were able to distinguish preoperative plasma samples and normal controls. MiRNAs with altered expression in both plasma and different adenoma tissues were identified. 3, 7 and 66 miRNAs expressed differentially between preoperative and postoperative plasma samples in growth hormone secreting, FSH/LH+ and hormone-immunonegative groups, respectively. MiR-143-3p was downregulated in late- but not in early postoperative plasma samples compared to preoperative ones exclusively in FSH/LH+ adenomas. Plasma level of miR-143-3p discriminated these samples with 81.8% sensitivity and 72.3% specificity (AUC=0.79; p=0.02).

CONCLUSIONS

Differentially expressed miRNAs in pituitary adenoma tissues have low abundance in plasma minimizing their role as biomarkers. Plasma miR-143-3p decreases in patients with FSH/LH+ adenoma indicated successful surgery, but its application for evaluating tumor recurrence needs further investigation.

Survivin as a potential therapeutic target of acetylsalicylic acid in pituitary adenomas

Acetylsalicylic acid (ASA) is known as a cancer preventing agent, but there is no data available regarding the effect of ASA on pituitary cells.

We investigated 66 nonfunctioning (NFPA) and growth hormone (GH)-producing adenomas and 15 normal pituitary samples. Functional assays (cell viability, proliferation, flow cytometry cell cycle analysis, caspase-3 activation and DNA degradation) were applied to explore the effect of ASA, YM155 (survivin inhibitor), survivin-targeting siRNA and TNF-related apoptosis-inducing ligand (TRAIL) in RC-4B/C and GH3 cells. Pituitary adenoma xenografts were generated in immunocompromised mice.

We found that survivin was overexpressed and TRAIL was downregulated in NFPAs compared to normal pituitary tissue. ASA decreased proliferation but did not induce apoptosis in pituitary cells. Additionally, ASA treatment decreased cells in S phase and increased cells in G2/M phase of the cell cycle. Inhibition of survivin using an inhibitor or siRNA-mediated silencing reversed the ASA-induced growth inhibition partially. In addition, we also found survivin-independent effects of ASA on the cell cycle that were mediated through inhibition of cyclin A, cyclin dependent kinase 2 (CDK2) and phospho-CDK2. We also aimed to test the effect of acetylsalicylic acid in an animal model using RC-4 B/C cells, but in contrast to GH3 cells, RC-4 B/C cells failed to adhere and grow a xenograft.

We concluded that ASA inhibited the growth of pituitary adenoma cells. Survivin inhibition is a key mechanism explaining its antineoplastic effects. Our results suggest that inhibition of survivin with small molecules or ASA could serve as potential therapeutic agents in NFPA.

[The role of miRNAs in the pathogenesis of pituitary adenomas]

MicroRNAs (miRNAs) are short, single stranded RNA molecules which play regulatory roles through posttranscriptional regulation of their target genes. Based on our current knowledge, more than 30% of the human protein-coding genes are regulated by miRNAs, hence influencing basic cellular mechanisms including cell proliferation, differentiation and cell death. Differential miRNA expression pattern has been detected in many different types of tumors and, recently, several publications have referred to miRNAs as potential therapeutic targets. Through adjustment of miRNA levels by artificial miRNAs administration or miRNA inhibition, we can influence not only one target gene but also complex biological pathways. Pituitary adenoma is the second most frequent intracranial tumor. In spite of this, the molecular mechanism of the pituitary adenoma formation is not yet entirely revealed. Recently, more and more evidences have been found suggesting that miRNAs have an important role in pituitary adenoma pathogenesis. Here, we summarize the recent results related to this role and highlight the therapeutic potentials in pituitary adenomas. Orv Hetil. 2018; 159(7): 252-259.

Systematic Investigation of Expression of G2/M Transition Genes Reveals CDC25 Alteration in Nonfunctioning Pituitary Adenomas

Dysregulation of G1/S checkpoint of cell cycle has been reported in pituitary adenomas. In addition, our previous finding showing that deregulation of Wee1 kinase by microRNAs together with other studies demonstrating alteration of G2/M transition in nonfunctioning pituitary adenomas (NFPAs) suggest that G2/M transition may also be important in pituitary tumorigenesis. To systematically study the expression of members of the G2/M transition in NFPAs and to investigate potential microRNA (miRNA) involvement. Totally, 80 NFPA and 14 normal pituitary (NP) tissues were examined. Expression of 46 genes encoding members of the G2/M transition was profiled on 34 NFPA and 10 NP samples on TaqMan Low Density Array. Expression of CDC25A and two miRNAs targeting CDC25A were validated by individual quantitative real time PCR using TaqMan assays. Protein expression of CDC25A, CDC25C, CDK1 and phospho-CDK1 (Tyr-15) was investigated on tissue microarray and immunohistochemistry. Several genes' expression alteration were observed in NFPA compared to normal tissues by transcription profiling. On protein level CDC25A and both the total and the phospho-CDK1 were overexpressed in adenoma tissues. CDC25A correlated with nuclear localized CDK1 (nCDK1) and with tumor size and nCDK1 with Ki-67 index. Comparing primary vs. recurrent adenomas we found that Ki-67 proliferation index was higher and phospho-CDK1 (inactive form) was downregulated in recurrent tumors compared to primary adenomas. Investigating the potential causes behind CDC25A overexpression we could not find copy number variation at the coding region nor expression alteration of CDC25A regulating transcription factors however CDC25A targeting miRNAs were downregulated in NFPA and negatively correlated with CDC25A expression. Our results suggest that among alterations of G2/M transition of the cell cycle, overexpression of the CDK1 and CDC25A may have a role in the pathogenesis of the NFPA and that CDC25A is potentially regulated by miRNAs.

Management of pineal region tumours

Pineal region tumours represent a colourful, challenging peculiarity of brain pathology. Views on their management are still much divided and controversial. Data of fifty patients with the whole palette of these tumours seen in the National Institute of Neurosurgery have been analysed in view of the result of management versus histology of these tumours. Findings of tumour marker studies have not at all been conclusive in predicting histology and outcome, however, cytology of the cerebrospinal fluid (CSF), if positive, pointed toward a very gloomy management result in all cases. Merits of infratentorial-supracerebellar, occipito-transtentorial approaches of direct surgery, palliative interventions and their timing, as well as that of irradiation are discussed in comparison with opinions and arguments from the literature. Shunt procedures alone proved to be dangerous in some cases by evoking haemorrhagic complications. In carefully selected cases microsurgical intervention gave the best possible results in expansively growing pineal region tumours. There is still place for irradiation and chemotherapy, again, in certain types of mass lesions.

[Neurovascular compression of the medulla oblongata: a rare cause of secondary hypertension]

Compression of the rostral ventrolateral medulla oblongata is one of the rarely identified causes of refractory hypertension. In patients with severe, intractable hypertension caused by neurovascular compression, neurosurgical decompression should be considered. The authors present the history of a 20-year-old man with severe hypertension. After excluding other possible causes of secondary hypertension, the underlying cause of his high blood pressure was identified by the demonstration of neurovascular compression shown by magnetic resonance angiography and an increased sympathetic activity (sinus tachycardia) during the high blood pressure episodes. Due to frequent episodes of hypertensive crises, surgical decompression was recommended, which was performed with the placement of an isograft between the brainstem and the left vertebral artery. In the first six months after the operation, the patient's blood pressure could be kept in the normal range with significantly reduced doses of antihypertensive medication. Repeat magnetic resonance angiography confirmed the cessation of brainstem compression. After six months, increased blood pressure returned periodically, but to a smaller extent and less frequently. Based on the result of magnetic resonance angiography performed 22 months after surgery, re-operation was considered. According to previous literature data long-term success can only be achieved in one third of patients after surgical decompression. In the majority of patients surgery results in a significant decrease of blood pressure, an increased efficiency of antihypertensive therapy as well as a decrease in the frequency of highly increased blood pressure episodes. Thus, a significant improvement of the patient's quality of life can be achieved. The case of this patient is an example of the latter scenario.

ACTH-secreting Crooke cell carcinoma of the pituitary

PURPOSE

While pituitary adenomas are common, pituitary carcinomas are rare. It is unclear whether pituitary carcinomas arise de novo or evolve from adenomas.

METHODS

We studied the clinical characteristics and tissue samples from eight pituitary surgeries and the autopsy from a patient with pituitary carcinoma. A 16-year-old female patient was diagnosed with an aggressive Crooke cell macroadenoma. Following transsphenoidal surgery, clinical signs of Cushing disease quickly reappeared. During the 14-year course of the illness, eight pituitary surgeries, three courses of extracranial irradiation and two (90) Yttrium-DOTATOC treatments were undertaken. A bilateral adrenalectomy was performed. The patient died of metastatic disease and uncontrolled hypercortisolism due to an adrenal remnant. A systematic morphologic study (histologic staining, electron microscopy) of all available surgical and autopsy specimens was undertaken.

RESULTS

Brisk mitotic activity, high Ki-67 and p53 immunolabelling were present in the pituitary samples from the onset. High proportion of tumour cells showed irregular nuclei and large nucleoli, and gradual increase in MGMT staining was observed. The tumour remained of Crooke cell type throughout the course. Autopsy disclosed a postirradiation sarcoma in the pituitary area.

CONCLUSIONS

The question whether pituitary carcinomas arise de novo or transform from an adenoma cannot be answered at present with certainty.

[Role of the intraoperative electrical brain stimulation in conserving the speech and language function in neurosurgical procedures on conscious patients]

AIM OF THE STUDY

To summarize the results gained with awake craniotomies, which were performed in either low grade glioma patients or epilepsy surgical patients whose tumor or epileptogenic zone, was in the vicinity of eloquent, mostly language, cortices. PATIENT SELECTION AND METHODS: In our retrospective study we selected 16 patients who were operated awake between 1999-2011 at the Neurosurgical Department of MAV Kórház Budapest, or at the National Institute of Neurosciences in Budapest, or at the Neurosurgical Department of the University of Debrecen in Debrecen. In the presurgical evaluation if it was possible we performed functional magnetic resonance imaging, tractography and detailed neuropsychological testing. At the National Institute of Neurosciences all patients were operated with the aid of MR guided neuronavigation.

RESULTS

Anesthesia was carried out without complications in all of the 16 cases. Monitoring of sleep deepness has significantly contributed to the safety of anesthesia during the superficial anesthezied states of the operation. The intraoperative neuropsychological tasks used for testing language were sensitive enough to judge the little disturbances in speech during stimulation. Stimulation evoked seizures could be adequately managed during surgery and did not influence the outcome of the procedures. The use of neuronavigation helped significantly by planning the optimal place for the craniotomy and by intraoperative orientation.

CONCLUSIONS

Awake craniotomies require well practiced surgical teams, which requires the cooperation of neuro-anesthesiologits, neurosurgeons, neuropsychologist and electrophysiologists. It has two goals, first to reduce the time of surgery to minimize surgical complications, secondly the detailed intraoperative mapping of cognitive and motor functions to avoid any neurological deficit. The intraoperative anatomical data provided by the neuronavigation and the functional data provided by awake intraoperative stimulation of the patient together serve the safety of the patient which is essential in the neurologically minimal invasive neurosurgical approach of the 21st century.

Neuroendocrine dysfunctions and their consequences following traumatic brain injury

Posttraumatic hypopituitarism is of major public health importance because it is more prevalent than previously thought. The prevalence of hypopituitarism in children with traumatic brain injury is unknown. Most cases of posttraumatic hypopituitarism remain undiagnosed and untreated in the clinical practice, and it may contribute to the severe morbidity seen in patients with traumatic brain injury. In the acute phase of brain injury, the diagnosis of adrenal insufficiency should not be missed. Determination of morning serum cortisol concentration is mandatory, because adrenal insufficiency can be life threatening. Morning serum cortisol lower than 200 nmol/L strongly suggests adrenal insufficiency. A complete hormonal investigation should be performed after one year of the trauma. Isolated growth hormone deficiency is the most common deficiency after traumatic brain injury. Sports-related chronic repetitive head trauma (because of boxing, kickboxing, football and ice hockey) may also result in hypopituitarism. Close co-operation between neurosurgeons, endocrinologists, rehabilitation physicians and representatives of other disciplines is important to provide better care for these patients. Orv. Hetil., 2012, 153, 927–933.

MicroRNA profile indicates downregulation of the TGFβ pathway in sporadic non-functioning pituitary adenomas

MicroRNAs (miRs) are small, 16-29 nucleotide long, non-coding RNA molecules which regulate the stability or translational efficiency of targeted mRNAs via RNA interference. MiRs participate in the control of cell proliferation, cell differentiation, signal transduction, cell death, and they play a role in carcinogenesis. The aims of our study were to analyse the expression profile of miRs in sporadic clinically non-functioning pituitary adenomas (NFPA) and in normal pituitary tissues, and to identify biological pathways altered in these pituitary tumors. MiR expression profiles of 12 pituitary tissue specimens (8 NFPA and 4 normal pituitary tissues) were determined using miR array based on quantitative real-time PCR with 678 different primers. Five overexpressed miRs and mRNA expression of Smads (Smad1-9), MEG and DLK1 genes were evaluated with individual Taqman assays in 10 NFPA and 10 normal pituitary tissues. Pathway analysis was performed by the DIANA-mirPath tool. Complex bioinformatical analysis by multiple algorithms and association studies between miRs, Smad3 and tumor size was performed. Of the 457 miRs expressed in both NFPA and normal tissues, 162 were significantly under- or overexpressed in NFPA compared to normal pituitary tissues Expression of Smad3, Smad6, Smad9, MEG and DLK1 was significantly lower in NFPA than in normal tissues. Pathway analysis together with in silico target prediction analysis indicated possible downregulation of the TGFβ signaling pathway in NFPA by a specific subset of miRs. Five miRs predicted to target Smad3 (miR-135a, miR-140-5p, miR-582-3p, miR-582-5p and miR-938) were overexpressed. Correlation was observed between the expression of seven overexpressed miRs and tumor size. Downregulation of the TGFβ signaling through Smad3 via miRs may have a possible role in the complex regulation of signaling pathways involved in the tumorigenesis process of NFPA.

[Familial isolated pituitary adenoma syndrome]

Familial pituitary adenomas occur in multiple endocrine neoplasia type 1, Carney complex, as well as in familial isolated pituitary adenoma syndrome. Familial isolated pituitary adenoma syndrome is an autosomal dominant disease with incomplete penetrance. Pituitary adenomas occur in familial setting but without any other specific tumors. In 20-40% of families with this syndrome, mutations have been identified in the aryl hydrocarbon receptor interacting protein gene while in the rest of the families the causative gene or genes have not been identified. Families carrying aryl hydrocarbon receptor interacting protein gene mutations have a distinct phenotype with younger age at diagnosis and a predominance of somatotroph and lactotroph adenomas. Germline mutations of the aryl hydrocarbon receptor interacting protein gene can be occasionally identified in usually young-onset seemingly sporadic cases. Genetic and clinical testing of relatives of patients with aryl hydrocarbon receptor interacting protein gene mutations can lead to earlier diagnosis and treatment at an earlier stage of the pituitary tumor.

[Consensus on the change of criteria for cure of acromegaly during the last decade]

The Acromegaly Consensus Group redefined the consensus criteria for cure of acromegaly. 74 neurosurgeons and experienced endocrinologists summarized the latest results on diagnosis and treatment of acromegaly. In this consensus statement the reliable growth hormone and insulin-like growth factor-1 assays were established. Definition of disease control was discussed based on the available publications and evidence. This short communication summarizes the clinical aspects of consensus criteria for diagnosis and cure of acromegaly based on the original article.

Diagnostic performance of salivary cortisol and serum osteocalcin measurements in patients with overt and subclinical Cushing's syndrome

OBJECTIVE

The cut-off value for salivary cortisol measurement for the diagnosis of Cushing's syndrome (CS) may depend both on the severity of the disease and the composition of control group. Therefore, we examined the utility of midnight salivary cortisol measurements in patients who were evaluated for signs and symptoms of CS or because they had adrenal incidentalomas. Because serum osteocalcin (OC) is considered as a sensitive marker of hypercortisolism, we also investigated whether OC could have a role in the diagnosis of CS.

PATIENTS AND METHODS

Each of the 151 patients was included into one of the following groups: (A) overt CS (n=23), (B) subclinical CS (n=18), (C) inactive adrenal adenomas (n=40), (D) patients without HPA disturbances (n=70). Patients (C+D) were used as controls. Serum, salivary and urinary cortisol, and OC were measured by electrochemiluminescence immunoassay.

RESULTS

Group A had suppressed OC as compared to both group B and group (C+D). Serum and salivary cortisol concentrations showed strong negative correlations with OC in patients with overt CS. The areas under the curves of salivary and serum cortisol at 24:00 h (0.9790 and 0.9940, respectively) serum cortisol after low dose dexamethasone test (0.9930) and OC (0.9220) obtained from ROC analysis for the diagnosis of overt CS were not statistically different.

CONCLUSION

This study confirms the usefulness of midnight salivary cortisol measurements in the diagnosis of overt CS in the everyday endocrinological praxis. Our results suggest that OC may have a role in the diagnosis of overt CS.

Down-regulation of Wee1 kinase by a specific subset of microRNA in human sporadic pituitary adenomas

CONTEXT

The tumorigenic mechanisms involved in pituitary adenomas, especially of nonfunctional pituitary adenomas (NFAs), remains unclear. Various cell cycle inhibitors have been found to be underexpressed in pituitary tumors; however, Wee1 kinase, a nuclear protein that delays mitosis and was recently recognized as a tumor suppressor gene, has not been previously investigated in pituitary tumors.

OBJECTIVE

Our objective was to examine the expression of Wee1 in pituitary tumors and to identify microRNAs (miRs) that can regulate its expression.

DESIGN

Expression of Wee1 was examined by immunohistochemistry and quantitative real-time PCR (qRT-PCR). Identification of miRs targeting the Wee1 3'-untranslated region was performed by miR array followed by expression analysis of identified miRs using qRT-PCR. Dual-luciferase assay and transient transfection of miRs into Hela cells followed by immunoblot analysis of Wee1 protein and cell proliferation analysis were carried out.

PATIENTS

A total of 57 pituitary tissue samples including 27 NFAs, 15 GH-producing adenomas with or without prolactin overproduction, and 15 normal pituitary glands were analyzed.

RESULTS

Wee1 protein expression was decreased in NFAs and GH-producing tumors with or without prolactin production, but no change in mRNA expression was observed with qRT-PCR. A specific subset of five miRNAs revealed by in silico target prediction was significantly overexpressed in NFA samples; three miRs (miR-128a, miR-155, and miR-516a-3p) targeted the 3'-untranslated region of the Wee1 transcript, and exogenous overexpression of these miRs inhibited Wee1 protein expression and HeLa cell proliferation.

CONCLUSIONS

To our knowledge, this is the first report suggesting that regulation of Wee1 kinase by miRs may be linked to pituitary tumorigenesis.

Dynamic changes of CB1-receptor expression in hippocampi of epileptic mice and humans

The endocannabinoid system plays a central role in retrograde synaptic communication, and controls both glutamatergic and gamma-aminobutyric acid (GABA)ergic transmission via type 1 cannabinoid (CB1) receptor. Both in sclerotic human hippocampi and in the chronic phase of pilocarpine-induced epilepsy in mice with sclerosis, CB1-receptor-positive interneuron somata were preserved both in the dentate gyrus and in the CA1 area, and the density of CB1-immunostained fibers increased considerably in the dentate molecular layer. This suggests that, although CB1 receptors are known to be reduced in density on glutamatergic axons, the CB1-receptor-expressing GABAergic axons sprout, or there is an increase of CB1-receptor levels on these fibers. The changes of CB1 immunostaining in association with the GABAergic inhibitory system appear to correlate with the severity of pyramidal cell loss in the CA1 subfield. These results confirm the involvement of the endocannabinoid system associated with GABAergic transmission in human temporal lobe epilepsy (TLE), as well as in the chronic phase of the pilocarpine model in mice. Pharmacotherapy aimed at the modulation of endocannabinoid-mediated retrograde synaptic signaling should take into account the opposite change in CB1-receptor expression observed on glutamatergic versus GABAergic axon terminals.

[Macroprolactinemia associated with pituitary macroadenoma: treatment with quinagolide]

According to current concept, macroprolactin is biologically inactive and, therefore, its accumulation in serum has little, if any, pathological significance. Authors present the history of a 80-year-old man who proved to have, among other associated disorders, an intra- and parasellar pituitary tumor measuring 21x12x12 mm in size which was revealed by pituitary MRI. His hormonal evaluation indicated a marked hyperprolactinemia mainly due to macroprolactinemia (total prolactin, 514 ng/ml; reference range, 1.6-10.7 ng/ml; macroprolactin 436 ng/ml, monomer prolactin 78.2 ng/ml). Tests for function of the pituitary-thyroid axis showed a mild subclinical primary hypothyroidism. The function of the pituitary-adrenal axis was normal, and other hormonal tests revealed low-normal serum gonadotropins and decreased testosterone level, whereas serum insulin-like growth factor I was normal. Although the majority of current guidelines state that dopamine-agonist treatment which is successfully used in prolactin-producing pituitary tumors and in other hyperprolactinemic disorders is unnecessary in patients with macroprolactinemia, the authors introduced a dopamine-agonist, quinagolide. During prolonged treatment, plasma prolactin returned close to the upper limit of normal (12.3 ng/ml) and 9 months after the beginning of treatment pituitary MRI showed a remarkable shrinkage of the pituitary tumor. Authors propose that in this patient the pituitary tumor secreted macroprolactin, and they recommend a treatment trial with dopamine-agonist in pituitary macroadenomas associated with macroprolactinemia.

[Intracranial propagation of invasive aspergilloma in an immuncompromised patient]

Aspergillus infection of the central nervous system is a rare disease, occasionally seen among immunocompromised patients. The most frequent pathway is hematogenic dissemination. Less known is the direct propagation from the paranasal sinuses, which is usually observed in immunocompetent patients. We report a patient who developed cavernous sinus syndrome due to an invasive intracranial aspergilloma after longlasting chemo- and steroid therapy for chronic lymphoid leukemia and immunhemolytic anemia. The characteristic features seen on radiological images--brain CT and MRI--suggested the possibility of invasive aspergilloma. Postoperative histology defined the diagnosis. Our case review highlights the importance of considering the possibility of an invasive opportunistic infection of the CNS in an immunocompromised patient presenting a new neurological sign.

[Outcome of somatostatin analogue treatment in acromegaly]

During the past decade the importance of medical therapy, especially treatment with somatostatin analogues has increased significantly in patients with active acromegaly.

AIMS

Authors analyzed the outcome of somatostatin analogue treatment in acromegalic patients evaluated and followed up at the 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, during the past 10 years.

PATIENTS AND METHODS

Changes in serum growth hormone (GH) and insulin-like growth factor-1 (IGF-1) concentration, as well as morphologic changes of pituitary adenomas followed by MRI scans were evaluated and compared in 32 acromegalic patients (26 women, 6 men) during long-term somatostatin analogue treatment (mean+/-SE, 3.1+/-0.3 years, range, 1-7 years). Primary somatostatin analogue treatment was applied in 10 patients (7 women and 3 men), whereas 15 patients (14 women and 1 man) had pituitary surgery and 7 patients (5 women and 2 men) underwent both pituitary surgery and irradiation therapy prior to somatostatin analogue treatment.

RESULTS

After a 3-month treatment with somatostatin analogues, both serum GH and IGF-1 levels decreased significantly and they remained around the same decreased levels throughout the treatment period. Serum GH decreased from 15.7+/-4.9 to 5.5+/-1.4 ng/ml, and serum IGF-1, expressed as a percentage of the upper limit of age- and sex-adjusted reference value, decreased from 204+/-14% to 135+/-12% at the end of treatment. The efficacy of somatostatin analogue treatment was not influenced by surgical or surgical and irradiation therapies which were applied prior to medical treatment. At the end of treatment 36.7% of patients had safe serum GH (<2.5 ng/ml), while serum IGF-1 returned below the upper limit of age- and sex-adjusted reference range in 41.4% of patients. Pituitary MRI showed regression of the adenoma in 46% of patients, and none of the patients had progression of the pituitary adenoma.

CONCLUSIONS

Somatostatin analogues are effective therapeutic options for acromegalic patients when primary surgical treatment cannot be performed due to complications and associated disorders, or in patients whose acromegaly remains active after pituitary surgery or after pituitary surgery and irradiation.

Protein western array analysis in human pituitary tumours: insights and limitations

The molecular analysis of pituitary tumours has received a great deal of attention, although the majority of studies have concentrated on the genome and the transcriptome. We aimed to study the proteome of human pituitary adenomas. A protein array using 1005 monoclonal antibodies was used to study GH-, corticotrophin- and prolactin-secreting as well as non-functioning pituitary adenomas (NFPAs). Individual protein expression levels in the tumours were compared with the expression profile of normal pituitary tissue. Out of 316 proteins that were detected in the pituitary tissue samples, 116 proteins had not previously been described in human pituitary tissue. Four prominent differentially expressed proteins with potential importance to tumorigenesis were chosen for validation by immunohistochemistry and western blotting. In the protein array analysis heat shock protein 110 (HSP110), a chaperone associated with protein folding, and B2 bradykinin receptor, a potential regulator of prolactin secretion, were significantly overexpressed in all adenoma subtypes, while C-terminal Src kinase (CSK), an inhibitor of proto-oncogenic enzymes, and annexin II, a calcium-dependent binding protein, were significantly underexpressed in all adenoma subtypes. The immunohistochemical analysis confirmed the overexpression of HSP110 and B2 bradykinin receptor and underexpression of CSK and annexin II in pituitary adenoma cells when compared with their corresponding normal pituitary cells. Western blotting only partially confirmed the proteomics data: HSP110 was significantly overexpressed in prolactinomas and NFPAs, the B2 bradykinin receptor was significantly overexpressed in prolactinomas, annexin II was significantly underexpressed in somatotrophinomas, while CSK did not show significant underexpression in any tumour. Protein expression analysis of pituitary samples disclosed both novel proteins and putative protein candidates for pituitary tumorigenesis, though validation using conventional techniques are necessary to confirm the protein array data.

[Evaluation of the accuracy of inferior petrosal sinus sampling in the differential diagnosis of ACTH-dependent Cushing's syndrome]

The differentiation of adrenocorticotropic hormone producing pituitary adenoma (Cushing's disease) from the ectopic ACTH syndrome is always a complex and difficult task, and in rare cases it is not possible to differentiate between the two disorders, even with the use of dynamic endocrine tests and the most advanced imaging techniques. Inferior petrosal sinus sampling (IPSS) with subsequent ACTH measurements became the gold-standard method of the differential diagnostic process. 34 patients with ACTH dependent Cushing's syndrome in whom the source of ACTH secretion couldn't be identified unambiguously with imaging techniques and/or dynamic endocrine tests underwent altogether 41 IPSS between 1999 and 2005. The sensitivity of the method was calculated on the basis of 31 samplings of 25 patients who had definite endocrinological diagnosis confirmed by the recovery from Cushing's syndrome after surgical intervention and/or by histological examinations (22 patients with ACTH-producing pituitary adenoma and 3 patients with ectopic ACTH syndrome). As a result of IPSS, pituitary-dependent Cushing's disease was diagnosed with a baseline central to peripheral ACTH ratio of >2.0 or with a ratio of >3.0 after corticotropin releasing hormone (CRH) administration. IPSS correctly identified ACTH-producing pituitary adenoma in 20 of 28 sampling procedures, with a sensitivity of 71.4%. Three patients had true negative and 8 had false negative results. There was no false positive result. Four of the 8 patients with false negative first sampling had a repeat sampling procedure leading to true positive result in each patient. In patients with Cushing's disease having true positive interventions, the basal and 5 minutes post-CRH ACTH concentrations were diagnostic in 14 and 19 cases, respectively. The sensitivity of IPSS within this series, reported for the first time from Hungary, was lower than it was found in much larger series published in international literature. In addition to technical difficulties, the lower sensitivity can be accounted also for the highly selected nature of the patient group.

A mutation and expression analysis of the oncogene BRAF in pituitary adenomas

OBJECTIVE

BRAF is an oncogene that is commonly mutated in both melanomas and papillary thyroid carcinomas, usually at position V600E that leads to constitutive activity in the Ras-mitogen-activated protein kinase (MAPK) pathway. We speculated that this same gene may be either mutated at this site, or overexpressed, in pituitary adenomas.

DESIGN AND MEASUREMENTS

We sequenced 37 pituitary adenomas for a mutation at the V600E position. In addition, we investigated B-Raf mRNA expression in normal pituitary (n = 5) and nonfunctioning pituitary adenomas (NFPA) (n = 6) by semiquantitative PCR, and in a further 27 pituitary adenomas of various types and 10 normal pituitaries using real-time quantitative PCR. Finally, we explored B-Raf protein expression in 10 normal pituitaries and 12 NFPAs.

RESULTS

No sequence mutations for the substitution V600E were identified. B-Raf mRNA was overexpressed in pituitary adenomas compared to normal pituitary, and this was entirely due to overexpression in NFPAs. NFPAs also showed very variable expression of B-Raf protein, but those tumours showing highest levels of B-Raf mRNA expressed the most B-Raf protein.

CONCLUSIONS

Mutations previously seen in the majority of melanomas and a substantial minority of papillary thyroid carcinomas are not a frequent finding in pituitary adenomas. However, overexpression of B-Raf mRNA and protein may be a feature of NFPAs, highlighting overactivity of the Ras-B-Raf-MAP kinase pathway in these tumours.

Pathological findings in cystic craniopharyngiomas after stereotactic intracavitary irradiation with yttrium-90 isotope

Histopathological, ultrastructural and polyacrylamide gel electrophoretic examinations were carried out on biopsy, cyst fluid, surgical pathology and autopsy specimens obtained from 7 cystic craniopharyngioma cases before and after yttrium-90 silicate colloid (90Y) irradiation. Light microscopy revealed that the lining epithelial tumor cell layer of the cyst wall was destroyed, and scar tissue containing large amount of hyaline degenerated collagen bundles replaced it. Proliferative postirradiation vasculopathy was also demonstrated in the cyst wall following 90Y installation. Electrophoretic property of cyst fluid was similar to the normal human serum. Considering that scar tissue has a certain propensity to shrink, the fibrosis in the cyst wall together with destruction of neoplastic epithelium and vascular changes might explain diminished fluid production and cyst volume reduction after 90Y treatment.

[Minimally invasive surgery of the pituitary and the sellar region]

INTRODUCTION

New minimal invasive neurosurgical approaches for the treatment of diseases in the sellar and perisellar regions (superciliary and paraseptal approach, perioperative ACTH measurements, application of endoscopes and neuronavigation) were introduced by the author. The modified surgical techniques were applied by the author successfully in the treatment of more than 1000 cases, of which the data of 746 patients were analysed and the results are presented.

METHODS AND RESULTS

The results of the clinical studies concerning superciliary and paraseptal approaches were as follows: length of the operations and, loss of blood were decreased, the patients needed shorter anesthesia and the treatment cost became lower. The approaches were performed without hair cutting with excellent cosmetic results leading to easier resocialisation of the patients. In the group of the patients operated on through the superciliary approach postoperative vasospasm developed in significantly lower rate, the number of days spent in the intensive care unit decreased and the rate of patients on discharge in good clinical condition were higher. The study on perioperative plasma ACTH simultaneous measurements with rapid and standard methods revealed first in the literature that, during anaesthesia in patients with ACTH producing adenoma the plasma ACTH level changed individually. There was no difference between arterial and venous plasma ACTH concentration in the same patient and the ACTH concentration in the bleedings from the peripituitary bony structures are individually variable, representing the network of the venous outflow of the pituitary. The decrease in the plasma ACTH concentrations in the peripheral venous samples two hours after operation and next morning proved the radical removal of the adenoma. The differences between concentrations in the left and right sides indicate the intrapituitary lateralization of the adenoma. The study on the usefulness of neuroendoscopy and neuronavigation in the author's hand revealed the advantages and disadvantages of these new neurosurgical instruments.

CONCLUSIONS

With the advent of the minimal invasive methods in surgery of the pituitary and the sellar region the mortality end the morbidity of the operations decreased.

[Radiotherapy of pituitary tumours]

In this article, the role of conventional radiotherapy and radiosurgery in the management of pituitary tumors is discussed. After a brief review about the mechanism of action and different techniques of irradiation therapy, the therapeutic effectiveness and side effects are analysed in the various types of pituitary tumors. Conventional fractionated radiotherapy has long been used to control growth and/or hormonal secretion of residual or recurrent pituitary tumors. Nevertheless, there is still a controversy concerning patient selection for radiotherapy, because several potentially significant side effects including hypopituitarism may develop. Stereotactic radiosurgical methods may have several advantages over conventional radiotherapy; they can be applied, for example, in patients with residual or recurrent pituitary tumors who had previously received conventional radiotherapy. However, long-term follow-up data with these relatively new techniques are still limited.

Somatostatin analogues stimulate p27 expression and inhibit the MAP kinase pathway in pituitary tumours

OBJECTIVES

Somatostatin (SST) analogues play an important role in the medical management of somatotroph pituitary adenomas and new agonists have the potential to be effective in a wider group of pituitary and other tumours. The anti-proliferative effect of SST occurs through multiple mechanisms, one of which is cell-cycle arrest, where p27, a cyclin-dependent kinase inhibitor, is an important regulator. We hypothesised that SST may upregulate p27 protein levels and downregulate the MAP kinase pathway in these tumours.

METHODS

Human pituitary adenoma cells and rat pituitary cell line (GH3) were cultured and treated in vitro with octreotide and the broad-spectrum SST agonist SOM230 (pasireotide). Immunoblotting for p27 and phospho-ERK (pERK) was performed and proliferation assessed by [3H]-thymidine incorporation. Histological samples from acromegalic patients treated with octreotide before surgery were immunostained for p27 and compared to samples from untreated patients matched for sex, age, tumour size, extension and invasiveness.

RESULTS

We detected upregulation of p27 protein levels with SST analogue treatment in vitro in human pituitary adenoma samples. pERK1/2 was inhibited by SST analogues in both the human samples and GH3 cells. SST and its analogues inhibited the proliferation of GH3 cells. p27 immunostaining was stronger in samples from patients with longer preoperative octreotide treatment (more than 6 months) than in samples from patients with shorter treatment periods.

CONCLUSIONS

This study demonstrates that SST-mediated growth inhibition is associated with the downregulation of pERK and upregulation of p27. More potent and broader-spectrum SST analogues are likely to play an increasing role in the treatment of tumours, where the MAP kinase pathway is overactivated.

The role of the superciliary approach in the surgical management of intracranial neoplasms

OBJECTIVE

The authors present and evaluate the experiences with 76 frontolateral keyhole craniotomies performed for supratentorial intracranial tumors via superciliary skin incisions.

METHOD

The exploration is a modification of the generally used pterional approach. Out of a series of 302 cases operated on with frontolateral keyhole craniotomies via superciliary skin incisions, 76 had various tumors at the frontal base, intra-, supra-, parasellar and intraorbital regions. The operations were carried out through a approximately 2.5 x 3 cm frontolateral miniaturized craniotomy following a skin incision at the upper edge of the eyebrow.

CONCLUSION

Despite the small size of craniotomy the superciliary approach is a suitable technique for resection of skull base tumors in the anterior fossa, orbit, sellar, parasellar and suprasellar regions. The exploration allows enough room for intracranial surgical manipulation with maximal protection of normal brain, vessel and nerve structures. The presented patients did not have any craniotomy-related complication.

Long-term outcome after temporal lobe surgery—Prediction of late worsening of seizure control

We analyzed possible predictors of late worsening of seizure control in 94 adult patients who had anterior temporal lobectomy (ATL) from the Epilepsy Center of the National Institute of Psychiatry and Neurology, Budapest between 1985 and 2001. We evaluated data regarding epilepsy, presurgical evaluation, pre- and postoperative EEG, structural imaging, histology and operative complications. The mean follow-up was 6.1 years (range: 2-17 years). The outcome was measured as Engel class, the time to the first seizure and the longest seizure free period. Multiple regression analysis was used to assess predictors. Seizure free outcome was achieved in 72% of the patients 1-year after surgery. Eighty-seven percent of them remained seizure free at the second year of follow-up, 74% at the fifth, and 67% at the tenth year of follow-up. After 2 years of follow-up improvement was present in 3%, worsening in 18% of the patients. Factors associated with long-term worsening were: postoperative ipsilateral EEG spikes over the resected side, preoperative bilateral interictal discharges, cortical dysplasia of Taylor's type, and ictal contralateral propagation. In these patients, even in seizure free state, therapy reduction might be inappropriate.

Treatment of pituitary tumors: radiation

In this paper, the role of conventional radiotherapy and radiosurgery in the management of pituitary tumors is reviewed. After a short summary of the mechanism of action of irradiation therapy and the types of different irradiation techniques, the therapeutic effects and side effects are analyzed in patients with different types of pituitary tumors, including our own experience with conventional radiotherapy and radiosurgery in patients with acromegaly. Conventional fractionated radiotherapy has long been used to control growth and/or hormonal secretion of residual or recurrent pituitary tumors. However, patient selection for conventional radiotherapy still remains a controversial issue, because a number of potentially significant side effects, including hypopituitarism and other complications, have been described. Stereotactic radiotherapy/radiosurgery methods have several potential advantages over conventional radiotherapy, including their use in patients with residual or recurrent pituitary tumors who had previously been treated by conventional radiotherapy, but long-term follow-up data with these relatively new techniques are still limited.

Differential gene expression in pituitary adenomas by oligonucleotide array analysis

OBJECTIVES

Microarray technology allows for the expression profile of many thousands of genes to be quantified at the same time, and has resulted in novel discoveries about the tumour biology of a number of cancers. We sought to do this in pituitary adenomas, the most common intracranial neoplasm.

METHODS

Affymetrix GeneChip HG-U133A oligonucleotide arrays covering 14 500 well-characterised genes from the human genome were used to study pooled RNA for each of the four major pituitary adenoma subtypes. Individual gene-expression levels in the tumours were compared relative to the expression profile in normal pooled pituitary RNA. Three differentially expressed genes with potential importance in tumourigenesis were chosen for validation by real-time quantitative PCR on the original tumours and on an additional 26 adenomas.

RESULTS

Bioinformatic analysis showed that 3906 genes and 351 expressed sequence tags were differentially expressed among all pituitary tumour subtypes. Lysosomal-associated protein transmembrane- 4-beta (LAPTM4B), a novel gene upregulated in hepatocellular carcinoma, was significantly over-expressed in adrenocorticotrophin (ACTH)-secreting adenomas and non-functioning pituitary adenomas (NFPAs). Bcl-2-associated athanogene (BAG1), an anti-apoptotic protein found at high levels in a number of human cancers, was significantly over-expressed in growth hormone-secreting and prolactin-secreting adenomas and NFPAs. The cyclin-dependent kinase inhibitor p18, in which murine gene deletion has been shown to produce pituitary ACTH cell hyperplasia and adenomas, was significantly under-expressed in ACTH-secreting adenomas.

CONCLUSIONS

Expression array analysis of pituitary adenomas using the Affymetrix GeneChip HG-U133A arrays appears to be a valid method of identifying genes that may be important in tumour pathogenesis.

Rapid re-enlargement of a macroprolactinoma after initial shrinkage in a young woman treated with bromocriptine

We report the case of a macroprolactinoma in a 32-year-old woman, who presented with secondary amenorrhea, galactorrhea, increased plasma prolactin level (3259 ng/ml), headache and bi-temporal visual field defect. Magnetic resonance imaging showed a large pituitary tumor. The patient responded well to bromocriptine (7.5 mg/day) with improvement of clinical symptoms and normalization of plasma prolactin within a few weeks. After 4 months of treatment, tumor size was also reduced markedly. During continued treatment at the same dose of bromocriptine the plasma prolactin level remained normal, but after 8 months of treatment the patient suddenly complained of worsening of her visual fields, and magnetic resonance imaging indicated re-enlargement of the tumor. Bromocriptine was discontinued and transsphenoidal pituitary surgery was performed. After surgery the visual field defect improved, but postoperative plasma prolactin level (1104 ng/ml) and magnetic resonance imaging indicated a residual tumor. Postoperative treatment with quinagolide (0.15 mg/day) resulted in disappearance of all clinical symptoms, normalization of prolactin level and a reduction in size of the residual tumor. This case demonstrates that a dissociation of the inhibitory effect of bromocriptine on tumor size and prolactin level may rarely develop during the course of drug treatment in a patient with macroprolactinoma.

Novel molecular aspects of pituitary adenomas

Ghrelin stimulates while somatostatin inhibits GH release and they thus serve as functional antagonists. We have compared their effects on cell proliferation. Ghrelin stimulates while somatostatin inhibits cell proliferation in most tissues and cell lines. Here we show that ghrelin and desoctanoyl ghrelin stimulate cell proliferation in rat pituitary cell line (GH3), and these effects could be inhibited with mitogen-activated protein kinase (MAPK), tyrosine kinase and protein kinase C inhibitors. Somatostatin and its analogs negatively regulate the growth of pituitary cells, and we now show that they inhibit MAPK activation. We hypothesised that one of the mechanisms involved in the somatostatin effect is a stimulation of cell cycle inhibitor p27, as pituitary adenomas have decreased p27 peptide content. Both octreotide and a new somatostatin analog SOM230 treatment resulted in an upregulation of p27 protein levels in human somatotrophinoma cells. In summary, we suggest that ghrelin and somatostatin have opposite effects on somatotroph cells not just at the level of GH release but also in terms of cell proliferation. Ghrelin may play a role in pituitary tumorigenesis via an autocrine/paracrine pathway. Our results also suggest that the antiproliferative effect of somatostatin analogs octreotide and SOM230 involve the up-regulation of p27 and down-regulation of the MAPK pathway in human somatotrophinomas.

Surviving CA1 pyramidal cells receive intact perisomatic inhibitory input in the human epileptic hippocampus

Temporal lobe epilepsy (TLE) is known to be linked to an impaired balance of excitation and inhibition. Whether inhibition is decreased or preserved in the human epileptic hippocampus, beside the excess excitation, is still a debated question. In the present study, quantitative light and electron microscopy has been performed to analyse the distribution, morphology and input-output connections of parvalbumin (PV)-immunopositive interneurons, together with the entire perisomatic input of pyramidal cells, in the human control and epileptic CA1 region. Based on the degree of cell loss, the patients with therapy-resistant TLE formed four pathological groups. In the non-sclerotic CA1 region of TLE patients, where large numbers of pyramidal cells are preserved, the number of PV-immunopositive cell bodies decreased, whereas axon terminal staining, and the distribution of their postsynaptic targets was not altered. The synaptic coverage of CA1 pyramidal cell axon initial segments (AISs) remained unchanged in the epileptic tissue. The somatic inhibitory input is also preserved; it has been decreased only in the cases with patchy pyramidal cell loss in the CA1 region (control, 0.637; epileptic with mild cell loss, 0.642; epileptic with patchy cell loss, 0.424 microm synaptic length/100 microm soma perimeter). The strongly sclerotic epileptic CA1 region, where pyramidal cells can hardly be seen, contains a very small number of PV-immunopositive elements. Our results suggest that perisomatic inhibitory input is preserved in the epileptic CA1 region as long as pyramidal cells are present. Basket and axo-axonic cells survive in epilepsy if their original targets are present, although many of them lose their PV content or PV immunoreactivity. An efficient perisomatic inhibition is likely to take part in the generation of abnormal synchrony in the non-sclerotic epileptic CA1 region, and thus participate in the maintenance of epileptic seizures driven, for example, by hyperactive afferent input.

In vivo laminar electrophysiology co-registered with histology in the hippocampus of patients with temporal lobe epilepsy

Laminar multiple microelectrodes have been developed to sample cortical and hippocampal activity in animals. If these measurements are adequately co-registered with the anatomy of the region, they can yield important information about its function and structure. In vivo laminar electrophysiological recordings from the human epileptic hippocampus are rare. However, histological and immunohistochemical analyses are widely used to determine the structural changes associated with temporal lobe epilepsy (TLE). Here we present data obtained by a combined approach: intraoperative recording of laminar field potentials, single and multiple unit activity under anesthesia, accompanied by histology and immunohistochemistry from the same hippocampal region of epileptic patients undergoing temporal lobectomy for drug-resistant TLE. The stability of the electrophysiology and the accuracy of its co-registration with histology were tested successfully. We have found large field potential spikes associated with bursting single units in CA1. Intracortical and subdural strip recordings from the lateral temporal cortex showed similar field potential activation patterns. A prominent oscillatory activity was present in the dentate gyrus with highly localized field potential gradient and multiple unit activity. This pattern could be used as a landmark defining the position of the electrode in the hippocampus. Our findings indicate that some aspects of the local and network epileptiform activity in the hippocampal formation are likely preserved under anesthesia. Electrophysiological identification of the functional state of the hippocampus together with its local structural correlates could further enhance our understanding of this disease.

[Surgical treatment of epilepsy]

In this article the possibilities, indications, methods and results of surgery in epilepsy are summarized in general with the Hungarian experience emphasized. Surgery may provide effective treatment in about 5-10% of the epileptic population. Surgical solution nowadays became an essential treatment in medial temporal epilepsy, if hippocampal sclerosis or other lesion is present, in therapy resistant lesional extratemporal epilepsies and in catastrophic childhood epilepsies if the epileptic disorder is restricted to one hemisphere (Rasmussen syndrome, hemimegalencephaly, Sturge-Weber disease and posttraumatic or postencephalitic hemispherial epilepsies). The algorithms of the presurgical evaluation and the current methods for study the pacemaker area, forbidden zones, and hemispherial functions are treated. The currently used type and techniques of surgery, such as lesionectomy, temporal lobe resections, hemispherotomy, callosotomy, multiple subpial transsections and their indications are described. The newest surgical approaches, as deep brain stimulation, vagal nerve stimulation, and irradiation techniques are also briefly touched. Lastly, we deal with prognostical factors of the surgical outcome, reasons of surgical failures and complications. In a brief chapter the importance of postsurgical rehabilitation is emphasized.

[Minimally invasive surgical techniques in the treatment of pituitary and peripituitary tumors: experience with the paraseptal approach]

INTRODUCTION

The direct endonasal, paraseptal approach, performed with the aid of an operating microscope, for removal of pituitary and peripituitary tumors has the potential advantage over the traditional sublabial, transseptal routes of minimizing postoperative rhinological complications, yet maintaining a high degree of efficacy and safety. Combination of this approach with the endoscope or neuronavigation may improve the effectiveness of the operation.

METHODS AND RESULTS

Between June, 2000 and June, 2003 two hundred and seventeen patients underwent 221 paraseptal operations for tumor removal at the National Institute of Neurosurgery, Budapest. To asses the effectiveness of this procedure, duration of the operation, tumor remission rates and surgical complications as well as postoperative complaints of patients were reviewed. Surgical remission rates for pituitary adenomas were as follows: 94% for microadenomas, 67% for macroadenomas and 29% for giant adenomas. There were five surgical complications and no operative deaths. Ten out of 12 patients, who had undergone transseptal surgery previously, preferred the endonasal approach in terms of pain and ease of recovery.

CONCLUSIONS

The direct paraseptal route for pituitary and pericellar tumor removal has an efficacy and complication rates comparable to those of the transseptal and sublabial routes. Patients generally recovered rapidly from this minimally invasive procedure and had no or minimal sinonasal complaints. For patients requiring a repeated operation, the paraseptal route appears to be less painful and easier to recover from, than the transseptal route.

The effect of gender and age on growth hormone replacement in growth hormone-deficient patients

We analyzed the effect of growth hormone replacement therapy (36 months) analyzed at a dose adjusted to maintain serum insulin-like growth factor-I level between the median and the upper end of the age-related reference range on bone mineral density, body composition, and carbohydrate metabolism with respect to gender and age in 20 adult patients (9 women, 11 men, mean age: 43 years, range: 21-61 years). The lumbar and femoral T-score was increased after 12 and after 18 months of therapy respectively in men (p < 0.001 and p = 0.002), but did not changed significantly in women. The increase of femoral T-score was greater in young men (< or = 45 years, n = 6) than old men (> 45 years, n = 5, p < 0.001). Body fat was lower in men than in women after 6 months (p = 0.002). The waist/hip ratio only decreased in women (p = 0.044). The waist circumference decreased in both genders after 6 months of therapy (p < 0.001), but more markedly in females than in males (p < 0.05). The sum of skinfold thicknesses was reduced in males after 6 months of therapy (p < 0.001). Changes in body composition parameters measured were independent of age. The glycosylated hemoglobin increased without sex or age difference after 12 months of initiation of therapy (p < 0.001), but fasting glucose and insulin levels did not change during the therapy. Our results indicate that the effect of growth hormone replacement on bone mineral content in adults is age- and gender-dependent, gender dependent on body composition, but independent of age and gender on carbohydrate metabolism.

Identification of adrenocorticotropin receptor messenger ribonucleic acid in the human pituitary and its loss of expression in pituitary adenomas

The ACTH receptor (ACTH-R) is the second member of the melanocortin (MC-2) receptor family that includes five seven-transmembrane G protein-coupled receptors and has been shown to be predominantly expressed in the adrenal cortex. It has been postulated that ACTH may regulate its own secretion through ultra-short-loop feedback within the pituitary. ACTH-secreting adenomas are characterized by resistance to glucocorticoid feedback, and they may have dysregulated ACTH feedback. We therefore investigated the ACTH-R in normal and adenomatous human pituitary tissue. We report here the identification of ACTH-R mRNA in the human pituitary gland, which was confirmed by direct sequencing. We studied the expression of the ACTH-R in 23 normal pituitary specimens and 53 pituitary adenomas (22 ACTH-secreting, nine GH-secreting, eight prolactin-secreting, one TSH-secreting, one FSH-secreting, 10 nonfunctioning, and two silent corticotroph adenomas), using the sensitive technique of real-time quantitative PCR. Contamination of ACTH-secreting adenomas and nonfunctioning pituitary adenomas with nonadenomatous tissue was excluded by lack of Pit-1 expression. ACTH-R mRNA was detected in all normal pituitary specimens, and in situ hybridization colocalized expression to ACTH staining cells only. However, ACTH-R mRNA levels were undetectable in 16 of 22 ACTH-secreting tumors and in both silent corticotroph tumors. Diagnostic preoperative plasma ACTH levels were significantly lower in the ACTH-R positive ACTH-secreting tumors, compared with those who were ACTH-R negative (P = 0.0006). Direct sequencing of the coding region of the ACTH-R in cDNA from three ACTH-secreting tumors positively expressing the receptor showed no mutations, as did sequencing of genomic DNA in three receptor negative ACTH-secreting tumors and the two silent corticotrophs. These results provide further evidence compatible with an ACTH feedback loop in the pituitary and suggest that loss of expression of the ACTH-R in corticotroph adenomas of patients with Cushing's disease may play a role in the resistance to feedback of the pituitary-adrenal axis seen in these patients.

[Epilepsy surgery in childhood: theory and practice]

1-1.5% of the Hungarian child population has epilepsy, and around 20% of them produces seizures in spite of modern antiepileptic drugs. A part of the pharmaco-resistant children may benefit from surgical removal of the epileptogenic focus. Presurgical evaluation has been developed a lot since the progress of neuroimaging, video-EEG monitoring, neuropsychology, and neurosurgical techniques in the 1990s. Authors summarize the important steps of presurgical evaluation in epileptic children emphasizing the role of history taking, physical examination, neuroimaging, standard EEG, long term monitoring, and neuropsychology. They describe the surgical treatment of the most important epilepsy syndromes in childhood analyzing the data of 58 epileptic children examined in the Bethesda Children's Hospital and operated in the National Institute of Neurosurgery (Budapest, Hungary). Age of children at surgery was between 16 months and 18 years, dysplasia and benign tumors covered etiology in 59% of the cases. The most frequent intervention was resection; however also some callosotomies and hemispherotomies were completed. Authors emphasize the importance of early surgical intervention of therapy resistant children in order to prevent the deteriorating effects of epilepsy on childhood psychomotor development.

Frontolateral keyhole craniotomy through a superciliary skin incision in children

INTRODUCTION

In our experience, frontolateral keyhole craniotomy in children is a safe approach for an experienced neurosurgeon to use in the treatment of the tumors or arachnoid cysts of the anterior fossa and sellar regions.

TECHNICAL NOTE

The authors describe the frontolateral keyhole craniotomy, which is a modification of the generally used pterional approach. The operations were carried out through an approximately 2.5 x 3-cm frontolateral miniaturized craniotomy after a skin incision just above the eyebrow. We adopted this technique in pediatric neurosurgery.

Thyrotropin secretion during oral glucose tolerance test in acromegalic patients and control subjects

It has been suggested that acute hyperglycemia stimulates somatostatin release from the hypothalamus, thus causing inhibition of growth hormone and thyrotropin secretion. Abnormal growth hormone secretory pattern to glucose load is characteristic of acromegaly, and it might reflect alterations in somatostatin release. We evaluated the sensitivity of serum thyrotropin response to presumed somatostatin inhibition during oral glucose tolerance test in 29 patients with active acromegaly, in 13 patients with inactive disease, and in 19 control persons suspected of impaired glucose tolerance. Both the acromegalic patients and the control subjects were euthyroid. Serum insulin, growth hormone, thyrotropin, free triiodthyronine, free thyroxine, and glucose were collected before and 30, 60, 90, and 120 min after the ingestion of 75 g glucose. While the free triiodthyronine and free thyroxine values did not change during the glucose test, the thyrotropin levels progressively and significantly declined in all groups. The basal to nadir thyrotropin ratio was higher in active acromegaly than in inactive disease and in control subjects (p < 0.01), suggesting that the glucose load inhibited thyrotropin stronger in active acromegalic patients. These data suggest that there is a possible strong somatostatin response to glucose load in acromegalic patients, which inhibits thyrotropin secretion. These data do not support the concept of decreased somatostatin drive in acromegaly.

Speech activation of language dominant hemisphere:

We tested the prediction that single photon emission computed tomography (SPECT) of the blood flow distribution in speech-activated brain identifies the language-dominant hemisphere. We based the prediction on the hypothesis that language activation leads to focally increased regional cerebral blood flow (rCBF), which is reflected in the uptake of a flow tracer recorded by SPECT. We compared the results of speech activation to the results of functional transcranial Doppler (fTCD) monitoring in the same subjects. Preoperatively, 17 patients (10 women and 7 men with a mean age of 36 +/- 15 years) with diagnoses of epilepsy (n = 14) or arteriovenous malformation (AVM) (n = 3) had two SPECT and two stereo-TCD monitoring studies in each case, one at rest, and one during 3 min of speech activation. Except for two left-handed patients with right-hemisphere dominance, the subjects had the highest changes of rCBF from baseline to activation in the left posterior inferior frontal cortex and in contralateral cerebellum. The results show that changes of the level of neuronal activity reflected by the measurement of rCBF variations might be detected by SPECT. Additionally, the evaluation of hemispheric language dominance based on SPECT showed a complete agreement with the evaluation based on fTCD results (yielding a kappa coefficient equal to 1), and therefore, speech-activation SPECT mapping might be helpful in the evaluation of hemispheric language dominance, especially when fMRI and PET are not available or they are contraindicated for some reason.

Reduced expression of the growth hormone and type 1 insulin-like growth factor receptors in human somatotroph tumours and an analysis of possible mutations of the growth hormone receptor

OBJECTIVE

Clinical acromegaly is characterized by elevated GH secretion in the presence of high circulating IGF-I levels. We hypothesized that the physiological IGF-I/GH negative feedback loop may be reset in somatotroph adenomas, specifically in terms of the level of expression of these receptors or mutations of the GH receptor (GH-R) in such tumours.

METHODS

We therefore investigated the full coding sequence of the GH-R in a series of somatotroph and other pituitary adenomas. We also investigated the mRNA expression of these putative feedback receptors in a series of pituitary adenomas and normal pituitary tissue, and their protein expression by immunostaining. Real-time RT-PCR assay was used for the quantification of the type 1 IGF receptor (IGF-R) and GH receptor (GH-R) mRNA, and sequence analysis was performed on the coding region of the GH-R gene.

RESULTS

No somatic mutations of the GH-R mRNA were detected in 18 GH-secreting tumours or two nonfunctioning pituitary adenomas (NFPAs). However, the levels of GH-R mRNA were significantly lower in both somatotroph tumours and NFPAs compared to the normal pituitary (P < 0.05 for both). Immunostaining for GH-R also showed significantly less GH-R expression in somatotroph adenomas compared to normal pituitary tissue (P < 0.0001). IGF-R mRNA levels were significantly lower in somatotroph tumours compared to normal pituitary (P = 0.005), and trended lower in corticotroph tumours (P = 0.07), while the other tumour types showed no significant difference from normal pituitary. Immunostaining for IGF-R also showed less IGF-R protein in the somatotroph adenomas compared to the normal pituitary tissue (P < 0.01).

CONCLUSIONS

Our findings suggest that decreased feedback inhibition of GH because of somatic mutations of the coding region of the GH-R are unlikely to be a common factor in the pathogenesis of these tumours. Nevertheless, decreased expression of the GH-R and of IGF-R in somatotroph tumours (both at the mRNA and protein level) may, at least in part, help explain the continuous secretion of GH from the tumour despite the high circulating levels of IGF-I and GH.

Synaptic reorganization of calbindin-positive neurons in the human hippocampal CA1 region in temporal lobe epilepsy

The distribution, morphology, synaptic coverage and postsynaptic targets of calbindin-containing interneurons and afferent pathways have been analyzed in the control and epileptic CA1 region of the human hippocampus. Numerous calbindin-positive interneurons are preserved even in the strongly sclerotic CA1 region. The morphology of individual cells is altered: the cell body and dendrites become spiny, the radially oriented dendrites disappear, and are replaced by a large number of curved, distorted dendrites. Even in the non-sclerotic epileptic samples, where pyramidal cells are present and calbindin-immunoreactive interneurons seem to be unchanged, some modifications could be observed at the electron microscopic level: they received more inhibitory synaptic input, and the calbindin-positive excitatory afferents - presumably derived from the CA1, the CA2 and/or the dentate gyrus - are sprouted. In the strongly sclerotic tissue, with the death of pyramidal cells, calbindin-positive terminals (belonging to interneurons and the remaining excitatory afferents) change their targets. Our data suggest that an intense synaptic reorganization takes place in the epileptic CA1 region, even in the non-sclerotic tissue, before the death of considerable numbers of pyramidal cells. Calbindin-positive interneurons participate in this reorganization: they show plastic changes in response to epilepsy. The enhanced inhibition of inhibitory interneurons may result in the disinhibition of pyramidal cells or in an abnormal synchrony in the output region of the hippocampus.