Intracerebral injection of oil cyst content of human craniopharyngioma (oil machinery fluid) as a toxic model in the rat brain

Clinical Significance of Plasma Leptin and Its Receptors mRNA Expression in Craniopharyngiomas: A Prospective Study

Craniopharyngioma (CP) is a benign tumor with a high rate of obesity and frequent recurrence. Moreover, the role of leptin/leptin receptors axis in obesity and the prognosis of CP is still unknown. Plasma leptin concentration and mRNA expression of leptin receptors were assessed in patients with CP. Moreover, the association between leptin/leptin receptors axis, weight-related outcomes, and progression-free survival (PFS) were explored in CP patients. Leptin receptors overexpressed in CP tumor tissue were compared to normal brain tissue (p < 0.05); compared to healthy controls, the concentration of leptin was elevated in CP with or without matched age, sex, and body mass index (BMI) (p < 0.05). The high plasma leptin level was an independent risk predictor for significant weight gain (adjusted odds ratio (aOR) = 2.29, and p = 0.030) and new-onset obesity (aOR = 6.64, and p = 0.016). High plasma leptin level (adjusted hazard ratio (aHR) = 3.74, and p = 0.011) and leptin receptor (LEPR) mRNA expression (aHR = 3.12, and p = 0.045) were independent risk factors for poor PFS in CP. Inappropriately elevated leptin relative to BMI and its failure to inhibit further weight gain indicate the existence of leptin resistance in patients with CP. Leptin and LEPR were independent predictors for PFS of patients with CP. The leptin/leptin receptors axis may be a potential therapeutic target for obesity in patients with CP.

Contemporary Biological Insights and Clinical Management of Craniopharyngioma

Craniopharyngiomas (CPs) are clinically aggressive tumors because of their invasive behavior and recalcitrant tendency to recur after therapy. There are 2 types based on their distinct histology and molecular features: the papillary craniopharyngioma (PCP), which is associated with BRAF-V600E mutations and the adamantinomatous craniopharyngioma (ACP), characterized by mutations in CTNNB1 (encoding β-catenin). Patients with craniopharyngioma show symptoms linked to the location of the tumor close to the optic pathways, hypothalamus, and pituitary gland, such as increased intracranial pressure, endocrine deficiencies, and visual defects. Treatment is not specific and mostly noncurative, and frequently includes surgery, which may achieve gross total or partial resection, followed by radiotherapy. In cystic tumors, frequent drainage is often required and intracystic instillation of drugs has been used to help manage cyst refilling. More recently targeted therapies have been used, particularly in PCP, but also now in ACP and clinical trials are underway or in development. Although patient survival is high, the consequences of the tumor and its treatment can lead to severe comorbidities resulting in poor quality of life, in particular for those patients who bear tumors with hypothalamic involvement. Accordingly, in these patients at risk for the development of a hypothalamic syndrome, hypothalamus-sparing treatment strategies such as limited resection followed by irradiation are recommended. In this review, we provide an update on various aspects of CP, with emphasis on recent advances in the understanding of tumor pathogenesis, clinical consequences, management, and therapies.

Inhibition of integrated stress response protects against lipid-induced senescence in hypothalamic neural stem cells in adamantinomatous craniopharyngioma

BACKGROUND

Adamantinomatous craniopharyngioma (ACP) is a benign tumor with malignant clinical manifestations. ACP adjacent to the hypothalamus often presents with more severe symptoms and higher incidence of hypothalamic dysfunction. However, the mechanism underlying hypothalamic dysfunction remains unclear.

METHODS

Immunostaining was performed to determine the nerve damage to the floor of the third ventricle (3VF) adjacent to ACP and to examine the recruitment and senescence of hypothalamic neural stem cells (htNSCs). The accumulation of lipid droplets (LDs) in htNSCs was evaluated via BODIPY staining, oil red O staining, and transmission electron microscopy. In vitro and in vivo assays were used to evaluate the effect of cystic fluid or oxidized low-density lipoprotein and that of oxytocin (OXT) on htNSC senescence and the hypothalamic function. The protein expression levels were analyzed using western blotting.

RESULTS

htNSCs with massive LD accumulation were recruited to the damaged 3VF adjacent to ACP. The LDs in htNSCs induced senescence and reduced neuronal differentiation; however, htNSC senescence was effectively prevented by inhibiting either CD36 or integrated stress response (ISR) signaling. Furthermore, OXT pretreatment reduced lipotoxicity via the inhibition of ISR signaling and the repair of the blood-brain barrier.

CONCLUSIONS

Reduced LD aggregation or ISR signaling inhibition prevented senescence in htNSCs and identified molecular pathways and potential therapeutic targets that may improve hypothalamic dysfunction in ACP patients.

Adamantinomatous craniopharyngioma cyst fluid can trigger inflammatory activation of microglia to damage the hypothalamic neurons by inducing the production of β-amyloid

INTRODUCTION

The mechanism by which adamantinomatous craniopharyngioma (ACP) damages the hypothalamus is still unclear. Cyst fluid rich in lipids and inflammatory factors is a characteristic pathological manifestation of ACP and may play a very important role in hypothalamic injury caused by tumors.

OBJECTIVE

The objective of this study was to construct a reliable animal model of ACP cyst fluid-induced hypothalamic injury and explore the specific mechanism of hypothalamic injury caused by cyst fluid.

METHODS

An animal model was established by injecting human ACP cyst fluid into the bilateral hypothalamus of mice. ScRNA-seq was performed on the mice hypothalamus and on an ACP sample to obtain a complete gene expression profile for analysis. Data verification was performed through pathological means.

RESULTS

ACP cystic fluid caused growth retardation and an increased obesity index in mice, affected the expression of the Npy, Fgfr2, Rnpc3, Sst, and Pcsk1n genes that regulate growth and energy metabolism in hypothalamic neurons, and enhanced the cellular interaction of Agrp-Mc3r. ACP cystic fluid significantly caused inflammatory activation of hypothalamic microglia. The cellular interaction of CD74-APP is significantly strengthened between inflammatory activated microglia and hypothalamic neurons. Beta-amyloid, a marker of neurodegenerative diseases, was deposited in the ACP tumor tissues and in the hypothalamus of mice injected with ACP cyst fluid.

CONCLUSION

In this study, a novel animal model of ACP cystic fluid-hypothalamic injury was established. For the first time, it was found that ACP cystic fluid can trigger inflammatory activation of microglia to damage the hypothalamus, which may be related to the upregulation of the CD74-APP interaction and deposition of β-amyloid, implying that there may be a similar mechanism between ACP cystic fluid damage to the hypothalamus and neurodegenerative diseases.

Hypothalamic syndrome

Hypothalamic syndrome (HS) is a rare disorder caused by disease-related and/or treatment-related injury to the hypothalamus, most commonly associated with rare, non-cancerous parasellar masses, such as craniopharyngiomas, germ cell tumours, gliomas, cysts of Rathke's pouch and Langerhans cell histiocytosis, as well as with genetic neurodevelopmental syndromes, such as Prader-Willi syndrome and septo-optic dysplasia. HS is characterized by intractable weight gain associated with severe morbid obesity, multiple endocrine abnormalities and memory impairment, attention deficit and reduced impulse control as well as increased risk of cardiovascular and metabolic disorders. Currently, there is no cure for this condition but treatments for general obesity are often used in patients with HS, including surgery, medication and counselling. However, these are mostly ineffective and no medications that are specifically approved for the treatment of HS are available. Specific challenges in HS are because the syndrome represents an adverse effect of different diseases, and that diagnostic criteria, aetiology, pathogenesis and management of HS are not completely defined.

Intraoperative Finding of an Anterior Communicating Artery Blister-Like Aneurysm During a Primary Craniopharyngioma Resection: Accidental or Incidental?

BACKGROUND

The presence of an anterior communicating artery blister-like aneurysm in the setting of a craniopharyngioma has never been reported to our knowledge.

CASE DESCRIPTION

This patient was admitted to our service for an untreated craniopharyngioma resection. An anterior interhemispheric approach with right frontal craniotomy was performed and a blister-like aneurysm of the anterior communicating artery was found during the surgery. After the tumor was completely resected, a suturing technique was used for the aneurysm. In this article, we are going to present this rare case and discuss the potential pathogeny of the aneurysm.

CONCLUSIONS

We hypothesized that cystic craniopharyngioma may rupture spontaneously. The cystic fluid accumulated in the lower subarachnoid space due to gravity, and it may lead to local vascular cytotoxic and inflammatory reactions which may result in the vascular wall remodeling and lead to the reconstructed vascular wall weakness.

Effects of craniopharyngioma cyst fluid on neurons and glial cells cultured from rat brain hypothalamus

Craniopharyngiomas (CPs) are rare, epithelial tumors of the central nervous system (CNS) that could lead to manifestation of multiple post-operative symptoms, ranging from hormonal imbalance to obesity, diabetes, visual, neurological and neurocognitive impairments. CP is more frequent in children, and has been reported in middle aged adults as well. In fact, arterial laceration and/or brain stroke which may occur following the removal of some CPs is mainly due to calcification of that CPs along with strong attachments to the blood vessels. The dense oily fluid content of CPs is reported to cause brain tissue damage, demyelination and axonal loss in the hypothalamus; however, its exact effect on different cell types of CNS is still unexplored. In this study, we have collected CP cyst fluid (CCF) from mostly young patients during surgical removal and exposed it 9-10 days in vitro to the primary cultures derived from rat brain hypothalamus for 48 h. A gradual decline in cell viability was noted with increasing concentration of CCF. Moreover, a distinct degenerative morphological transformation was observed in neurons and glial cells, including appearance of blebbing and overall reduction of the cell volume. Further, enhanced expression of Caspase-3 in neurons and glial cells exposed to CCF by immunofluorescence imaging, supported by Western blot experiment suggest CCF induced apoptosis of hypothalamic cells in culture. In this study, we have demonstrated the deleterious effects of the cyst fluid on various cell types within the tumors originating region of the brain and its surroundings for the first time. Taken together, this finding could be beneficial towards identifying the region specific toxic effects of the cyst fluid and its underlying mechanism.

Characterization of the murine orthotopic adamantinomatous craniopharyngioma PDX model by MRI in correlation with histology

PURPOSE

Adamantinomatous craniopharyngiomas (ACP) as benign sellar brain tumors are challenging to treat. In order to develop robust in vivo drug testing methodology, the murine orthotopic craniopharyngioma model (PDX) was characterized by magnetic resonance imaging (MRI) and histology in xenografts from three patients (ACP1-3).

METHODS

In ACP PDX, multiparametric MRI was conducted to assess morphologic characteristics such as contrast-enhancing tumor volume (CETV) as well as functional parameters from dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) including area-under-the-curve (AUC), peak enhancement (PE), time-to-peak (TTP) and apparent diffusion coefficient (ADC). These MRI parameters evaluated in 27 ACP PDX were correlated to histological features and percentage of vital tumor cell content.

RESULTS

Qualitative analysis of MRI and histology from PDX revealed a similar phenotype as seen in patients, although the MRI appearance in mice resulted in a more solid tumor growth than in humans. CETV were significantly higher in ACP2 xenografts relative to ACP1 and ACP3 which correspond to respective average vitality of 41%, <10% and 26% determined histologically. Importantly, CETV prove tumor growth of ACP2 PDX as it significantly increases in longitudinal follow-up of 110 days. Furthermore, xenografts from ACP2 revealed a significantly higher AUC, PE and TTP in comparison to ACP3, and significantly increased ADC relative to ACP1 and ACP3 respectively. Overall, DCE-MRI and DWI can be used to distinguish vital from non-vital grafts, when using a cut off value of 15% for vital tumor cell content.

CONCLUSIONS

MRI enables the assessment of craniopharyngioma PDX vitality in vivo as validated histologically.

Proteomics in pediatric cystic craniopharyngioma

Adamantinomatous craniopharyngioma (ACP) is still often burdened by a poor prognosis in children as far as the risk of recurrence and the quality of life are concerned. Therefore, many efforts are now dedicated to investigate the molecular characteristics of this tumor aiming at finding new therapeutic options. ACP is prevalently a cystic lesion so that an increasing number of researches are focused on the analysis of its cystic content. In the present article, the main results of the current proteomic analysis (PA) on the ACP fluid are summarized. Both "bottom-up" and "top-down" approaches have been utilized. In the bottom-up approach, proteins and peptides are enzymatically or chemically digested prior to liquid chromatography and mass spectrometry analyses. The bottom-up approach pointed out several proteins of the inflammation (namely, α2-HS-glycoprotein, α1-antichymotrypsin and apolipoproteins) as possibly involved in the genesis and growth of the cystic component of ACP. The top-down strategy analyzes proteins and peptides in the intact state, making it particularly suitable for the identification of peptides and low molecular weight proteins and for the characterization of their possible isoforms and post-translational modifications. The top-down approach disclosed the presence of the thymosin β family. Thymosin β4, in particular, which is involved in the cytoskeleton organization and migration of several tumors, could play a role in the progression of ACP. Finally, PA was utilized to investigate alterations in cyst fluid character after treatment with interferon-α. The analyzed samples showed a progressive reduction of the levels of α-defensins (proteins involved in the inflammatory-mediated response) after the intracystic injection of interferon-α, thus reinforcing the hypothesis that inflammation contributes to ACP cyst pathogenesis. Additional studies on the solid component of ACP are still necessary to further validate the previous results and to identify possible markers for targeted therapy.

Molecular pathology of adamantinomatous craniopharyngioma: review and opportunities for practice

Since the first identification of CTNNB1 mutations in adamantinomatous craniopharyngioma (ACP), much has been learned about the molecular pathways and processes that are disrupted in ACP pathogenesis. To date this understanding has not translated into tangible patient benefit.

The recent development of novel techniques and a range of preclinical models now provides an opportunity to begin to support treatment decisions and develop new therapeutics based on molecular pathology.

In this review the authors summarize many of the key findings and pathways implicated in ACP pathogenesis and discuss the challenges that need to be tackled to translate these basic science findings for the benefit of patients.

Ultrastructural characterization of craniopharyngioma at the tumor boundary: A structural comparison with an experimental toxic model using "oil machinery" fluid, with emphasis on Rosenthal fibers

Craniopharyngiomas (CPs) are cystic, encapsulated, slow-growing epithelial tumors. CPs can be aggressive forms invading and resorting surrounding structures of adjacent brain tissue, where Rosenthal fibers (RFs) are expressed. The aim of this study was to investigate the ultrastructure of these fibers in human biopsies and compare it with an experimental toxic model produced by the cortical infusion of the oil cyst fluid ("Oil machinery" fluid or OMF) from CPs to rats. For this purpose, the CPs from ten patients were examined by light and electron microscopy. OMF was administered to rats intracortically. Immunohistochemical detection of glial fibrillary acidic protein (GFAP) and vimentin was assessed. In both freshly obtained CPs and rat brain tissue, the presence of abundant cellular debris, lipid-laden macrophages, reactive gliosis, inflammation and extracellular matrix destruction were seen. Ultrastructural results suggest focal pathological disturbances and an altered microenvironment surrounding the tumor-brain junction, with an enhanced presence of RFs in human tumors. In contrast, in the rat brain different degrees of cellular disorganization with aberrant filament-filament interactions and protein aggregation were seen, although RFs were absent. Our immunohistochemical findings in CPs also revealed an enhanced expression of GFAP and vimentin in RFs at the peripheral, but not at the central (body) level. Through these findings we hypothesize that the continuous OMF release at the CPs boundary may cause tissue alterations, including damaging of the extracellular matrix, and possibly contributing to RFs formation, a condition that was not possible to reproduce in the experimental model. The presence of RFs at the CPs boundary might be considered as a major criterion for the degree of CPs invasiveness to normal tissue. The lack of RFs reactivity in the experimental model reveals that the invasive component of CPs is not present in the OMF, although the fluid per se can exert tissue damage.

Craniopharyngioma: Survivin expression and ultrastructure

The aim of the present study was to investigate the significance of survivin protein expression levels in craniopharyngioma. Tumor samples and clinical data were obtained from 50 patients with craniopharyngioma who were admitted to the West China Hospital of Sichuan University (Chengdu, China). The morphology of the craniopharyngioma samples was observed using optical and electron microscopes, and survivin expression was investigated in the samples by immunohistochemical analysis. The immunohistochemical results revealed survivin expression in all of the craniopharyngioma samples, but not in the healthy brain tissue samples. It was identified that survivin was expressed at a higher level in cases of the adamantinomatous type compared with those of the squamous-papillary type, in male patients compared with female patients, in children compared with adults and in recurrent cases compared with non-recurrent cases. Furthermore, no significant difference was detected in survivin expression levels among the tumors of different subtypes and different disease stages. The results of the present study indicate that survivin is significant in the development of craniopharyngioma, and that survivin protein expression levels are a meaningful indicator for assessing craniopharyngioma recurrence.