DNA Methylation Pattern in Somatotroph Pituitary Neuroendocrine Tumors.

INTRODUCTION: Growth hormone secretion by sporadic somatotroph neuroendocrine pituitary tumors (PitNETs) is a major cause of acromegaly. These tumors are relatively heterogenous in terms of histopathological and molecular features. Our previous transcriptomic profiling of somatotroph tumors revealed three distinct molecular subtypes. This study aimed to investigate the difference in DNA methylation patterns in subtypes of somatotroph PitNETs and its role in distinctive gene expression. METHODS: Genome-wide DNA methylation was investigated in 48 somatotroph PitNETs with EPIC microarrays. Gene expression was assessed with RNAseq. Bisulfite pyrosequencing and qRT-PCR were used for verifying the results of DNA methylation and gene expression. RESULTS: Clustering tumor samples based on methylation data reflected the transcriptome-related classification. Subtype 1 tumors are densely granulated without GNAS mutation, characterized by high expression of NR5A1 (SF-1) and GIPR. The expression of both genes is correlated with specific methylation of the gene body and promoter. This subtype has a lower methylation level of 5' gene regions and CpG islands than the remaining tumors. Subtype 2 PitNETs are densely granulated and frequently GNAS-mutated, while those in subtype 3 are mainly sparsely granulated. Methylation/expression analysis indicates that ∼50% genes located in differentially methylated regions are those differentially expressed between tumor subtypes. Correlation analysis revealed DNA methylation-controlled genes, including CDKN1B, CCND2, EBF3, CDH4, CDH12, MGMT, STAT5A, PLXND1, PTPRE, and MMP16, and genes encoding ion channels and semaphorins. CONCLUSION: DNA methylation profiling confirmed the existence of three molecular subtypes of somatotroph PitNETs. High expression of NR5A1 and GIPR in subtype 1 tumors is correlated with specific methylation of both genes.

Lysine Methyltransferase 5A Promotes the Progression of Growth Hormone Pituitary Neuroendocrine Tumors through the Wnt/ß-Catenin Signaling Pathway.

INTRODUCTION: Growth hormone (GH) secreting pituitary adenoma is considered one of the most harmful types of Pituitary Neuroendocrine Tumors (PitNETs). Our previous research has found that high expression of Lysine methyltransferase 5A (KMT5A) is closely related to the proliferation of PitNETs. The aim of this study was to investigate the role and molecular mechanism of KMT5A in the progression of GH PitNETs. METHODS: Immunohistochemistry, qRT-PCR, and Western blot (WB) were used to assess the expression levels of KMT5A in human normal pituitary and GH PitNETs, as well as in rat normal pituitary and GH3 cells. Additionally, we utilized RNA interference technology and treatment with a selective KMT5A inhibitor to decrease the expression of KMT5A in GH3 cells. CCK-8, EdU, flow cytometry (FCM), clone formation, and WB assay were further employed to evaluate the impact of KMT5A on the proliferation of GH3 cells in vitro. A xenograft model was established to evaluate the role of KMT5A in GH PitNETs progression in vivo. RESULTS: KMT5A was highly expressed in GH PitNETs and GH3 cells. Moreover, the reduction of KMT5A expression led to inhibited growth of GH PitNETs and increased apoptosis of tumor cells, as indicated by the findings from CCK-8, EdU, clone formation, and FCM assays. Additionally, WB analysis identified the Wnt/ß-catenin signaling pathway as a potential mechanism through which KMT5A promotes GH PitNETs progression. CONCLUSION: Our research suggests that KMT5A may facilitate the progression of GH PitNETs via the Wnt/ß-catenin signaling pathway. Therefore, KMT5A may serve as a potential therapeutic target and molecular biomarker for GH PitNETs.

MiR-320a Acts as a Tumor Suppressor in Somatotroph Pituitary Neuroendocrine Tumors by Targeting BCAT1.

INTRODUCTION: Aberrant miR-320a has been reported to be involved in the tumorigenesis of several cancers. In our previous study, we identified the low expression of circulating miR-320a in patients with somatotroph pituitary neuroendocrine tumor (PitNET); however, the role of miR-320a in somatotroph PitNET proliferation is still unclear. METHODS: Cell viability and colony formation assays were used to detect the effect of miR-320a and BCAT1 on GH3 cells. TargetScan was used to identify the target genes of miR-320a. Dual-luciferase reporter gene assay was used to explore the relation between miR-320a and BCAT1. Transcriptome and proteome analyses were performed between somatotroph PitNETs and healthy controls. The expression level of miR-320a in somatotroph PitNETs were detected by RT-qPCR and Western blot. RESULTS: miR-320a mimics inhibit cell proliferation, while miR-320a inhibitors promote cell proliferation in GH3 cells. An overlap analysis using a Venn diagram revealed that BCAT1 is the only target gene of miR-320a overexpressed in somatotroph PitNETs compared to healthy controls, as revealed by both microarray and proteomics results. A dual-luciferase reporter gene assay showed that miR-320a may bind to the BCAT1-3'UTR. The transfection of miR-320a mimics downregulated the expression and miR-320a inhibitors and upregulated the expression of BCAT1 in GH3 cells. The interference of BCAT1 expression in GH3 cells downregulated cell proliferation and growth. Pan-cancer analyses demonstrated that high BCAT1 expression often indicates a poor prognosis. CONCLUSION: Our findings illustrate that miR-320a may function as a tumor suppressor and BCAT1 may promote tumor progression. miR-320a may inhibit the growth of somatotroph PitNETs by targeting BCAT1.

Immunological signatures and predictive biomarkers for first-generation somatostatin receptor ligand resistance in Acromegaly.

PURPOSE: Predicting resistance to first-generation Somatostatin Receptor Ligands (fg-SRL) in Acromegaly patients remains an ongong challenge. Tumor-associated immune components participate in various pathological processes, including drug-resistance. We aimed to identify the immune components involved in resistance of fg-SRL, and to investigate biomarkers that can be targeted to treat those drug-resistant Acromegaly. METHODS: We conducted a retrospective study involving 35 Acromegaly patients with somatotropinomas treated postoperatively with fg-SRL. Gathering clinicopathological data, SSTR2 expression, and immunological profiles, we utilized univariate, binary logistic regression, and ROC analyses to assess their predictive roles in fg-SRL resistance. Spearman correlation analysis further examined interactions among interested characteristics. RESULTS: 19 patients (54.29%) exhibited resistance to postoperative fg-SRL. GH level at diagnosis, preoperative tumor volume, T2WI-MRI intensity, granularity, PD-L1, SSTR2, and CD8 + T cell infiltration showed association with clinical outcomes of fg-SRL. Notably, T2WI-MRI hyperintensity, PD-L1-IRS > 7, CD8 + T cell infiltration < 14.8/HPF, and SSTR2-IRS < 5.4 emerged as reliable predictors for fg-SRL resistance. Correlation analysis highlighted a negative relationship between PD-L1 expression and CD8 + T cell infiltration, while showcasing a positive correlation with preoperative tumor volume of somatotropinomas. Additionally, 5 patients with fg-SRL resistance underwent re-operation were involved. Following fg-SRL treatment, significant increases in PD-L1 and SSTR5 expression were observed, while SSTR2 expression decreased in somatotropinoma. CONCLUSION: PD-L1 expression and CD8 + T cell infiltration, either independently or combined with SSTR2 expression and T2WI-MRI intensity, could form a predictive model guiding clinical decisions on fg-SRL employment. Furthermore, targeting PD-L1 through immunotherapy and embracing second-generations of SRL with higher affinity to SSTR5 represent promising strategies to tackle fg-SRL resistance in somatotropinomas.

Suspected silent pituitary somatotroph neuroendocrine tumor associated with acromegaly-like bone disorders: a case report.

BACKGROUND: Growth hormone (GH) positive pituitary neuroendocrine tumors do not always cause acromegaly. Approximately one-third of GH-positive pituitary tumors are classified as non-functioning pituitary tumors in clinical practice. They typically have GH and serum insulin-like growth factor 1 (IGF-1) levels in the reference range and no acromegaly-like symptoms. However, normal hormone levels might not exclude the underlying hypersecretion of GH. This is a rare and paradoxical case of pituitary tumor causing acromegaly-associated symptoms despite normal GH and IGF-1 levels. CASE PRESENTATION: We report a case of a 35-year-old woman with suspicious acromegaly-associated presentations, including facial changes, headache, oligomenorrhea, and new-onset diabetes mellitus and dyslipidemia. Imaging found a 19 × 12 × 8 mm pituitary tumor, but her serum IGF-1 was within the reference, and nadir GH was 0.7ng/ml after glucose load at diagnosis. A thickened skull base, increased uptake in cranial bones in bone scan, and elevated bone turnover markers indicated abnormal bone metabolism. We considered the pituitary tumor, possibly a rare subtype in subtle or clinically silent GH pituitary tumor, likely contributed to her discomforts. After the transsphenoidal surgery, the IGF-1 and nadir GH decreased immediately. A GH and prolactin-positive pituitary neuroendocrine tumor was confirmed in the histopathologic study. No tumor remnant was observed three months after the operation, and her discomforts, glucose, and bone metabolism were partially relieved. CONCLUSIONS: GH-positive pituitary neuroendocrine tumors with hormonal tests that do not meet the diagnostic criteria for acromegaly may also cause GH hypersecretion presentations. Patients with pituitary tumors and suspicious acromegaly symptoms may require more proactive treatment than non-functioning tumors of similar size and invasiveness.

Surgical and non-surgical interventions for primary and salvage treatment of growth hormone-secreting pituitary adenomas in adults.

BACKGROUND: Growth hormone (GH)-secreting pituitary adenoma is a severe endocrine disease. Surgery is the currently recommended primary therapy for patients with GH-secreting tumours. However, non-surgical therapy (pharmacological therapy and radiation therapy) may be performed as primary therapy or may improve surgical outcomes. OBJECTIVES: To assess the effects of surgical and non-surgical interventions for primary and salvage treatment of GH-secreting pituitary adenomas in adults. SEARCH METHODS: We searched CENTRAL, MEDLINE, WHO ICTRP, and ClinicalTrials.gov. The date of the last search of all databases was 1 August 2022. We did not apply any language restrictions. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs of more than 12 weeks' duration, reporting on surgical, pharmacological, radiation, and combination interventions for GH-secreting pituitary adenomas in any healthcare setting. DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles and abstracts for relevance, screened for inclusion, completed data extraction, and performed a risk of bias assessment. We assessed studies for overall certainty of the evidence using GRADE. We estimated treatment effects using random-effects meta-analysis. We expressed results as risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI) or mean differences (MD) for continuous outcomes, or in descriptive format when meta-analysis was not possible. MAIN RESULTS: We included eight RCTs that evaluated 445 adults with GH-secreting pituitary adenomas. Four studies reported that they included participants with macroadenomas, one study included a small number of participants with microadenomas. The remaining studies did not specify tumour subtypes. Studies evaluated surgical therapy alone, pharmacological therapy alone, or combination surgical and pharmacological therapy. Methodological quality varied, with many studies providing insufficient information to compare treatment strategies or accurately judge the risk of bias. We identified two main comparisons, surgery alone versus pharmacological therapy alone, and surgery alone versus pharmacological therapy and surgery combined. Surgical therapy alone versus pharmacological therapy alone Three studies with a total of 164 randomised participants investigated this comparison. Only one study narratively described hyperglycaemia as a disease-related complication. All three studies reported adverse events, yet only one study reported numbers separately for the intervention arms; none of the 11 participants were observed to develop gallbladder stones or sludge on ultrasonography following surgery, while five of 11 participants experienced any biliary problems following pharmacological therapy (RR 0.09, 95% CI 0.01 to 1.47; 1 study, 22 participants; very low-certainty evidence). Health-related quality of life was reported to improve similarly in both intervention arms during follow-up. Surgery alone compared to pharmacological therapy alone may slightly increase the biochemical remission rate from 12 weeks to one year after intervention, but the evidence is very uncertain; 36/78 participants in the surgery-alone group versus 15/66 in the pharmacological therapy group showed biochemical remission. The need for additional surgery or non-surgical therapy for recurrent or persistent disease was described for single study arms only. Surgical therapy alone versus preoperative pharmacological therapy and surgery Five studies with a total of 281 randomised participants provided data for this comparison. Preoperative pharmacological therapy and surgery may have little to no effect on the disease-related complication of a difficult intubation (requiring postponement of surgery) compared to surgery alone, but the evidence is very uncertain (RR 2.00, 95% CI 0.19 to 21.34; 1 study, 98 participants; very low-certainty evidence). Surgery alone may have little to no effect on (transient and persistent) adverse events when compared to preoperative pharmacological therapy and surgery, but again, the evidence is very uncertain (RR 1.23, 95% CI 0.75 to 2.03; 5 studies, 267 participants; very low-certainty evidence). Concerning biochemical remission, surgery alone compared to preoperative pharmacological therapy and surgery may not increase remission rates up until 16 weeks after surgery; 23 of 134 participants in the surgery-alone group versus 51 of 133 in the preoperative pharmacological therapy and surgery group showed biochemical remission. Furthermore, the very low-certainty evidence did not suggest benefit or detriment of preoperative pharmacological therapy and surgery compared to surgery alone for the outcomes 'requiring additional surgery' (RR 0.48, 95% CI 0.05 to 5.06; 1 study, 61 participants; very low-certainty evidence) or 'non-surgical therapy for recurrent or persistent disease' (RR 1.22, 95% CI 0.65 to 2.28; 2 studies, 100 participants; very low-certainty evidence). None of the included studies measured health-related quality of life. None of the eight included studies measured disease recurrence or socioeconomic effects. While three of the eight studies reported no deaths to have occurred, one study mentioned that overall, two participants had died within five years of the start of the study. AUTHORS' CONCLUSIONS: Within the context of GH-secreting pituitary adenomas, patient-relevant outcomes, such as disease-related complications, adverse events and disease recurrence were not, or only sparsely, reported. When reported, we found that surgery may have little or no effect on the outcomes compared to the comparator treatment. The current evidence is limited by the small number of included studies, as well as the unclear risk of bias in most studies. The high uncertainty of evidence significantly limits the applicability of our findings to clinical practice. Detailed reporting on the burden of recurrent disease is an important knowledge gap to be evaluated in future research studies. It is also crucial that future studies in this area are designed to report on outcomes by tumour subtype (that is, macroadenomas versus microadenomas) so that future subgroup analyses can be conducted. More rigorous and larger studies, powered to address these research questions, are required to assess the merits of neoadjuvant pharmacological therapy or first-line pharmacotherapy.

Clinical Characteristics and Management of Cosecreting Thyroid Stimulating Hormone or Prolactin Pituitary Growth Hormone Adenomas: A Case-Control Study.

OBJECTIVE: Cosecreting thyroid stimulating hormone (TSH) or prolactin (PRL) in patients with pituitary growth hormone (GH) adenomas has been rarely reported. Our study aimed to elucidate their clinical characteristics. METHODS: We retrospectively collected data of 22 cases of cosecreting GH and TSH pituitary adenomas [(GH+TSH)oma] and 10 cases of cosecreting GH and PRL pituitary adenomas [(GH+PRL)oma] from Beijing Tiantan Hospital, Capital Medical University between January 2009 and January 2023. The clinical manifestation, preoperative hormone levels, imaging features, pathologic characteristics, and biochemical remission rates were compared among 335 patients with solo-secreting GH adenomas (GHoma) and 49 patients with solo-secreting TSH adenoma (TSHoma). Patients with (GH+TSH)oma and (GH+PRL)oma were grouped according to biochemical remission to explore the risk factors leading to biochemical nonremission. RESULTS: Cosecreting pituitary GH adenomas had various clinical manifestations and a larger tumor volume and were more likely to invade the cavernous sinus bilaterally and compress the optic chiasm. GH and TSH levels were lower in (GH+TSH)oma than in GHoma or TSHoma. Solo part remission was observed both in (GH+TSH)oma and (GH+PRL)oma. Cavernous sinus invasion was an independent risk factor for biochemical nonremission in patients with (GH+TSH)oma and (GH+PRL)oma. CONCLUSIONS: The clinical manifestation of (GH+TSH)oma and (GH+PRL)oma may be atypical. When screening for pituitary adenomas, a comprehensive evaluation of all pituitary target gland hormones is needed. Cosecreting pituitary GH adenomas are more aggressive and surgery is often unable to completely remove the tumor, requiring pharmacologic or radiological treatment if necessary. Clinicians should give high priority to biochemical remission, although solo part remission may occur.

Real-life data of Pasireotide LAR in acromegaly: a long-term follow-up.

OBJECTIVE: Pasireotide LAR (PAS-LAR) was released in Italy in 2017 to treat acromegaly patients resistant to SRLs (Somatostatin Receptors Ligands). The long-term follow-up data of PAS-LAR therapy in Italy are limited. This study aimed to evaluate the efficacy and safety of PAS-LAR in acromegaly. DESIGN: Patients with acromegaly in PAS-LAR treatment were enrolled in three tertiary Italian endocrinological centers and evaluated by a retrospective observational real-life multicentre study. METHODS: Patients have been studied before (baseline) and 1, 6, 12, 24 and > 36 months after PAS-LAR start. Clinical, biochemical, and pituitary magnetic resonance data were collected, along with information on adverse events. Acromegaly disease activity was classified according to the IGF-1 index (normal value < 1.0). RESULTS: Fifty patients (female 23) were enrolled. PAS-LAR treatment (mean follow-up 24 ± 16 months) significantly decreased IGF-1 levels (IGF-1 index baseline vs last visit: 1.9 ± 0.6 vs 1.2 ± 0.6, p < 0.0001). At the last visit, 67% of patients had controlled disease, and 44% showed a decrease in tumor volume. Clinical and biochemical efficacy was observed as early as after 1-month of PAS-LAR treatment (IGF-1 index baseline vs 1-month: 1.9 ± 0.6 vs 1.4 ± 0.7, p < 0.0001). Also, 50% of patients referred headache improvement or disappearance. Fifteen patients discontinued PAS-LAR due to failure of treatment and poor glycaemic control. The prevalence of diabetes increased from 33% at the baseline to 54% at the last visit (p = 0.0072). CONCLUSION: In real-life settings, PAS-LAR significantly decreases symptoms, IGF-1 levels, and the size of adenoma in patients with acromegaly resistant to SRLs. Beneficial effects may occur early after the first injection.

Caloric restriction as a possible pitfall for persistent acromegaly follow-up - case report.

BACKGROUND: Acromegaly diagnosis is established when plasma levels of IGF-1 are increased and the Oral Glucose Tolerance Test (OGTT) with 75gr of glucose can't suppress Growth Hormone (GH) levels. These two parameters are also useful during follow-up, after surgical/radiologic therapy and/or during medical therapy. CASE PRESENTATION: A 29-year-old woman was diagnosed with acromegaly after a severe headache. Previous amenorrhea and facial and acral changes were noticed. A pituitary macroadenoma was found, biochemical evaluation was in agreement with the suspected acromegaly and a transsphenoidal adenectomy was performed. As the disease recurred, a surgical reintervention and radiosurgery (Gamma Knife, 22 Gy) were necessary. No normalization of IGF-1 was achieved during three years after radiosurgery. Surprisingly, then, and although clinical features seemed getting worse, IGF-1 levels became consistently controlled to 0.3-0.8 times the upper limit of the reference range. Questioned, the patient referred that she was following an intermittent fasting dietary plan. However, based on the dietary questionnaire, she was found to be under severe caloric restriction. First OGTT (under caloric restriction) showed absence of GH suppression and an IGF-1 value of 234 ng/dL (Reference Range 76-286 ng/mL). A second OGTT, one month after an eucaloric diet was instituted, showed an increased IGF-1 of 294 ng/dL, maintaining an unsuppressed, yet less elevated, GH. CONCLUSIONS: GHRH/GH/IGF-1 axis controls somatic growth. Regulation is complex, and nutrition status and feeding pattern have a recognized role. Like systemic inflammation or chronic liver disease, fasting and malnutrition decrease the expression of hepatic GH receptors, with consequent reduction of IGF-1 levels, through resistance to GH. This clinical report shows that caloric restriction may represent a pitfall in acromegaly follow-up.

Refractory somatotroph adenomas.

Somatotroph adenomas are usually controlled with standard therapy, which can include surgery, medical treatment and radiotherapy. Some tumors have a more aggressive behavior and are refractory to standard therapy. In this review, we summarize the phenotype of these tumors and the current options for their management.

Vascular anomalies in patients with growth hormone-secreting pituitary adenomas: illustrative case report and systematic review of the literature.

PURPOSE: Endonasal resection is the first-line treatment for patients harboring growth hormone (GH)-secreting pituitary adenomas. The complexity of the parasellar neurovascular structures makes pre-operative diagnostic imaging essential to understanding the anatomy of this region. We aimed to describe vascular anomalies in acromegalic patients and emphasize their relevance for surgery and preoperative planning. METHODS: A systematic review following the PRISMA statement was performed in July 2021. RESULTS: Thirty-three studies were evaluated. Elevated GH and insulin-like growth factor-1 (IGF-1) levels are linked to the occurrence of cardiovascular risk factors. This is attributed to endothelial dysfunction, mainly caused by changes in flow-mediated dilatation (FMD), which is probably the main cause of vascular anomalies in acromegaly. The occurrence of protrusions of the internal carotid artery (ICA) (35-53%), a narrow intercarotid distance, and an asymmetrical course was described. In 13-18% of acromegalic patients, the presence of an intracerebral aneurysm could be reported (incidence in the general population:0.8-1.3%). The selected studies were however performed with a small patient sample (range:1-257). We present a case report of a 57y/o male patient with anomalies of the ICA ("kissing carotid arteries") harboring a GH-secreting adenoma, which was resected via an endoscopic endonasal approach. CONCLUSIONS: There is an association between acromegaly and endothelial dysfunction, which increases cardiovascular risk factors and vascular anomalies. Preoperative vascular imaging, e.g., CT angiography, should be implemented as a standard to identify patients at risk and estimate surgical morbidity. However, no evidence-based recommendations exist so far, so future studies are necessary.

Clinical and prognostic significance of granulation patterns in somatotroph adenomas/tumors of the pituitary: a meta-analysis.

INTRODUCTION: Sparsely granulated somatotroph adenoma/tumor (SGST) is thought to be more clinically aggressive than densely granulated somatotroph adenoma/tumor (DGST). However, the literature is not entirely consistent as to the disparate demographic and behavioral features of these subtypes. In this study, we conducted a meta-analysis to further clarify the demographic, clinicopathological, prognostic, and molecular characteristics of SGST versus DGST. METHODS: We accessed two electronic databases to search for potential data. Pooled estimates of odds ratio (OR), mean difference (MD), and corresponding 95% confidence interval (CI) were calculated using the random-effect model. RESULTS: SGST was associated with younger patient age and lower male-to-female ratio (p < 0.001) compared to DGST. Clinically, SGST had larger tumor size and high rate of cavernous sinus and suprasellar extension (p < 0.001) than DGST. During postoperative follow-up, SGST was associated with a lower endocrinological remission rate (OR 0.60; 95% CI 0.40 to 0.90; p = 0.01) and a poorer response rate to SRL (OR 0.16; 95% CI 0.08-0.35; p < 0.001) in comparison to DGST. The prevalence of GSP mutations was significantly lower in SGST (OR 0.36; 95% CI 0.17 to 0.79; p = 0.01). CONCLUSION: SGST and DGST were demographically, clinicopathologically, and molecularly different from each other with the former associated with adverse treatment outcomes and poor response to medical therapy. There are still gaps in translational studies that could help us better understand the behavior of these tumors and identify potential targets in the treatment of sparsely granulated tumors.

Clinical characteristics and therapeutic outcomes of acromegalic patients with giant growth hormone-secreting pituitary adenomas: a single-center study of 67 cases.

PURPOSE: Acromegalic patients with giant growth hormone-secreting pituitary adenomas (GHPAs) (≥ 40 mm) are relatively rare, and their clinical characteristics and treatment outcome data are limited. This study aims to analyze the clinical practice experience of giant GHPAs. METHODS: Sixty-seven acromegalic patients with giant GHPAs and 67 patients with macro GHPAs (10-39 mm), matched for age and gender from the same hospital during the same period, were retrospectively recruited. The clinical characteristics, treatment, and outcomes were analyzed. RESULTS: Enlargement of the extremities and facial features were the most common symptoms in most patients (92.5%). Compared with the macroadenoma group, more frequent visual impairment (86.6% vs. 25.4%, P < 0.001) and gonadal axis dysfunction (49.3% vs. 34.3%, P = 0.008), higher preoperative fasting GH, nadir GH after OGTT and IGF-1 levels, and a higher proportion of extrasellar tumor invasion were seen in the giant adenoma group. As the adenoma size increases, the total resection rate decreases, and postoperative complications and multimodal treatment strategies increase significantly. Fasting and nadir GH levels remained higher at 1 week postoperatively, and there were more surgical complications and cases of anterior hypopituitarism in the giant group. After a median follow-up of 36 months, 12 patients (36.4%) in the giant GHPA group and 17 (36.2%) in the macro GHPA group achieved biochemical remission. Other factors such as age of onset, age of diagnosis, delayed diagnosis time, metabolic complications, p53 positive rate, and Ki-67 index showed no significant difference between the two groups. CONCLUSIONS: With aggressive multimodal therapy, the biochemical remission rate of acromegalic patients with giant GHPAs is comparable to that of patients with macro adenoma. However, postoperative complications and hypopituitarism need to be closely monitored.

Neuromedin B receptor as a potential therapeutic target for corticotroph adenomas.

PURPOSE: Cushing's disease (CD) results from autonomous adrenocorticotropic hormone (ACTH) secretion by corticotroph adenomas, leading to excessive cortisol production, ultimately affecting morbidity and mortality. Pasireotide is the only FDA approved tumor directed treatment for CD, but it is effective in only about 25% of patients, and is associated with a high rate of hyperglycemia. Neuromedin B (NMB), a member of the bombesin-like peptide family, regulates endocrine secretion and cell proliferation. Here, we assessed NMB and NMB receptor (NMBR) expression in human corticotroph adenomas and the effects of NMBR antagonist PD168368 on murine and human corticotroph tumors. METHODS: To investigate NMB and NMBR expression, real-time qPCR and immunostaining on human pathological specimens of corticotroph, non-functional and somatotroph adenomas were performed. The effects of PD168368 on hormone secretion and cell proliferation were studied in vitro, in vivo and in seven patient-derived corticotroph adenoma cells. NMB and NMBR were expressed in higher extent in human corticotroph adenomas compared with non-functional or somatotroph adenomas. RESULTS: In murine AtT-20 cells, PD168368 reduced proopiomelanocortin (Pomc) mRNA/protein expression and ACTH secretion as well as cell proliferation. In mice with tumor xenografts, tumor growth, ACTH and corticosterone were downregulated by PD168368. In patient-derived adenoma cells, PD168368 reduced POMC mRNA expression in four out of seven cases and ACTH secretion in two out of five cases. A PD168368-mediated cyclin E suppression was also identified in AtT-20 and patient-derived cells. CONCLUSION: NMBR antagonist represents a potential treatment for CD and its effect may be mediated by cyclin E suppression.

The Effect and Potential Mechanism Analysis of Growth Hormone-Secreting Pituitary Adenomas on Thyroid Function.

OBJECTIVE: Current studies on the effect of high growth hormone (GH)/insulin-like growth factor (IGF)-1 on thyroid function are inconsistent. The aim was to explore the effect and potential mechanism of high GH/IGF-1 on thyroid function by analyzing the changes of thyroid function in patients with growth hormone-secreting pituitary adenoma (GHPA). METHODS: This was a retrospective cross-sectional study. Demographic and clinical data of 351 patients with GHPA who were first admitted to Beijing Tiantan Hospital, Capital Medical University, from 2015 to 2022 were collected to analyze the relationship between high GH/IGF-1 levels and thyroid function. RESULTS: GH was negatively correlated with total thyroxine (TT4), free thyroxine (FT4), and thyroid-stimulating hormone (TSH). IGF-1 was positively correlated with total triiodothyronine (TT3), free triiodothyronine (FT3), and FT4 and negatively correlated with TSH. Insulin-like growth factor-binding protein (IGFBP)-3 was positively correlated with TT3, FT3, and FT3:FT4 ratio. The FT3, TT3, TSH, and FT3:FT4 ratio of patients with GHPA and diabetes mellitus (DM) were significantly lower than those with GHPA but without DM. With the increase of tumor volume, thyroid function gradually decreased. GH and IGF-1 were correlated negatively with age in patients with GHPA. CONCLUSION: The study emphasized the complex interaction between the GH and the thyroid axes in patients with GHPA and highlighted the potential effect of glycemic status and tumor volume on thyroid function.

Novel AIP mutation in exon 6 causing acromegaly in a German family.

The most frequent genetic alteration of familial isolated growth hormone producing pituitary neuroendocrine tumors is a germline mutation of the aryl hydrocarbon receptor-interacting protein (AIP) gene. Various AIP mutations are already known; however, an AIP mutation in exon 6 (c.811_812del; p.Arg271Glyfs*16) has not been reported yet. Here, we report a German family with two identical twins who were both affected by acromegaly and carried the above-mentioned novel AIP mutation. The father was found to be an unaffected carrier, while the paternal aunt most likely suffered from acromegaly as well and died from metastatic colorectal cancer. Apart from reporting a novel AIP mutation, this study does not only highlight the different clinical and histological features of the AIP mutated growth hormone producing pituitary neuroendocrine tumors but also confirms the poor responsiveness of dopamine agonists in AIP mutated acromegaly. Furthermore, it highlights the increased mortality risk of comorbidities typically associated with acromegaly.

Predictors of postoperative biochemical remission in lower Knosp grade growth hormone-secreting pituitary adenomas: a large single center study.

PURPOSE: Growth hormone-secreting pituitary adenomas (GH-PAs) with a low Knosp grade are typically associated with a good postoperative biochemical remission (BR) rate. However, a proportion of patients do not achieve remission. In this study, we aimed to investigate predictive factors of postoperative remission for lower Knosp GH-PAs. METHODS: In this retrospective study, we enrolled 140 patients who were diagnosed with lower Knosp (0-2) GH-PAs and received trans-sphenoidal surgery between December 2016 and June 2021 from the largest pituitary tumor surgery center in southern China. The univariate, binary Logistic regression, and receiver operating characteristic curve (ROC) analyses were employed to determine independent predictors and cutoff values of remission. The postoperative outcome was defined as remission using the 2010 consensus criteria of acromegaly. RESULTS: One hundred and thirty six patients (97.1%) achieved gross total resection. The postoperative long-term BR was 68.6%. Empty sella, tumor maximum diameter and postoperative GH levels were independent factors predicting remission. ROC revealed that postoperative 24 h GH ≤ 1.3 ng/mL and ≤ 1.23 ng/mL were valuable predictors for 3-month and long-term remission respectively, and that postoperative 3-month GH ≤ 1.6 ng/mL and tumor maximum diameter ≤ 17 mm were predictors for delayed remission. CONCLUSION: Early postoperative GH levels can be used as predictors of remission. However, BR was not associated with preoperative somatostatin analogs therapy or Knosp grade (0-2). For patients without residual tumor or recurrence and whose GH levels are slightly elevated within 1 year after surgery, adjuvant treatments may not be necessary.

Low frequency of AIP mutations in patients with young-onset sporadic pituitary macroadenomas.

PURPOSE: Mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene cause familial isolated pituitary adenomas (FIPA). AIP mutations have also been found in patients with apparently sporadic pituitary adenomas, particularly in young patients with large adenomas. The aim of this study was to determine the frequency of AIP germline mutations in patients with young-onset sporadic pituitary macroadenomas. METHODS: The AIP gene was sequenced in 218 Portuguese patients with sporadic pituitary macroadenomas diagnosed before the age of 40 years. RESULTS: Heterozygous rare sequence variants in AIP were identified in 18 (8.3%) patients. However, only four (1.8%) patients had pathogenic or likely pathogenic variants. These consisted of two already known mutations (p.Arg81* and p.Leu115Trpfs*41) and two novel mutations (p.Glu246*, p.Ser53Thrfs*36). All four patients had GH-secreting adenomas diagnosed between the ages of 14 and 25 years. The frequency of AIP pathogenic or likely pathogenic variants in patients under the age of 30 and 18 years was 3.4% and 5.0%, respectively. CONCLUSION: The frequency of AIP mutations in this cohort was lower than in other studies. Previous reports may have overestimated the contribution of AIP mutations due to the inclusion of genetic variants of uncertain significance. The identification of novel AIP mutations expands the known spectrum of genetic causes of pituitary adenomas and may help understand the role of AIP mutations in the molecular mechanisms underlying pituitary tumorigenesis.

Long-term control of acromegaly after pituitary surgery in South-Eastern Norway.

PURPOSE: Sustained cure of acromegaly can only be achieved by surgery. Most growth hormone (GH) secreting pituitary adenomas are macroadenomas (≥ 10 mm) at diagnosis, with reported surgical cure rates of approximately 50%. Long-term data on disease control rates after surgery are limited. Our aim was to estimate short- and long-term rates of biochemical control after pituitary surgery in acromegaly and identify predictive factors. METHODS: Patients operated for GH-secreting pituitary adenomas between 2005-2020 were included from the local pituitary registry (n = 178). Disease activity and treatment data were recorded at one-year (short-term) and five-year (long-term) postoperative follow-up. Biochemical control was defined as insulin-like growth factor 1 (IGF-1) ≤ 1.2 × upper limit of normal value. Multivariate regression models were used to identify factors potentially predicting biochemical control. RESULTS: A total of 178 patients with acromegaly (median age at diagnosis 49 (IQR: 38-59) years, 46% women) were operated for a pituitary adenoma. Biochemical control was achieved by surgery in 53% at short-term and 41% at long-term follow-up, without additional treatment for acromegaly. Biochemical control rates by surgery were of same magnitude in paired samples (45% vs. 41%, p = 0.213) for short- and long-term follow-up, respectively. At short-term, 62% of patients with microadenomas and 51% with macroadenomas, achieved biochemical control. At long-term, the biochemical control rate was 58% for microadenomas and 37% for macroadenomas (p = 0.058). With adjunctive treatment, 82% achieved biochemical control at long-term. Baseline IGF-1 levels significantly predicted biochemical control by surgery at short-term (OR: 0.98 (95% CI: 0.96-0.99), p = 0.011), but not at long-term (OR: 0.76 (95% CI: 0.57-1.00), p = 0.053). CONCLUSION: In unselected patients with acromegaly, the long-term biochemical control rate remains modest. Our findings indicate a need to identify patients at an earlier stage and improve therapeutic methods and surgical outcomes.

The Methylation Analysis of the Glucose-Dependent Insulinotropic Polypeptide Receptor (GIPR) Locus in GH-Secreting Pituitary Adenomas.

The glucose-dependent insulinotropic polypeptide receptor (GIPR) is aberrantly expressed in about one-third of GH-secreting pituitary adenomas (GH-PAs) and has been associated with a paradoxical increase of GH after a glucose load. The reason for such an overexpression has not yet been clarified. In this work, we aimed to evaluate whether locus-specific changes in DNA methylation patterns could contribute to this phenomenon. By cloning bisulfite-sequencing PCR, we compared the methylation pattern of the GIPR locus in GIPR-positive (GIPR+) and GIPR-negative (GIPR-) GH-PAs. Then, to assess the correlation between Gipr expression and locus methylation, we induced global DNA methylation changes by treating the lactosomatotroph GH3 cells with 5-aza-2'-deoxycytidine. Differences in methylation levels were observed between GIPR+ and GIPR- GH-PAs, both within the promoter (31.9% vs. 68.2%, p < 0.05) and at two gene body regions (GB_1 20.7% vs. 9.1%; GB_2 51.2% vs. 65.8%, p < 0.05). GH3 cells treated with 5-aza-2'-deoxycytidine showed a ~75% reduction in Gipr steady-state level, possibly associated with the observed decrease in CpGs methylation. These results indicate that epigenetic regulation affects GIPR expression in GH-PAs, even though this possibly represents only a part of a much more complex regulatory mechanism.