Three-Dimensional Cell Culture Systems in Pediatric and Adult Brain Tumor Precision Medicine

Primary brain tumors often possess a high intra- and intertumoral heterogeneity, which fosters insufficient treatment response for high-grade neoplasms, leading to a dismal prognosis. Recent years have seen the emergence of patient-specific three-dimensional in vitro models, including organoids. They can mimic primary parenteral tumors more closely in their histological, transcriptional, and mutational characteristics, thus approximating their intratumoral heterogeneity better. These models have been established for entities including glioblastoma and medulloblastoma. They have proven themselves to be reliable platforms for studying tumor generation, tumor-TME interactions, and prediction of patient-specific responses to establish treatment regimens and new personalized therapeutics. In this review, we outline current 3D cell culture models for adult and pediatric brain tumors, explore their current limitations, and summarize their applications in precision oncology.

MODL-10. Tumor-brain-organoids as a model for pediatric brain tumors research

BACKGROUND: Embryonal brain neoplasms like atypical teratoid rhabdoid tumor (ATRT) or embryonal tumor with multilayered rosettes (ETMR) still have a very poor outcome despite intensive treatment including chemotherapy, irradiation and surgery. To date, precision oncology has identified clinically relevant innovative therapeutic targets only for a minor subpopulation of pediatric brain tumor patients, which may be due to current in vitro screens not recapitulating the cellular heterogeneity and cellular interactions in vivo. As cellular heterogeneity and cellular interactions majorly influence the response of tumor cells to treatment, we established an innovative 3D screening platform that combines human neural tissue surrounding primary tumor tissue. METHODS: We established a model of tumor-brain-organoids (TBO) by incorporating embryonal tumor cells (ATRT and ETMR tumor cells) into hiPSC-derived forebrain organoids. Using whole mount immunostaining (WMI), we evaluated cancer-phenotype, the neuronal and progenitor cell distribution in brain organoids, and we performed drug screening analysis. Furthermore, we used single-cell RNA-sequencing to characterize the cellular heterogeneity and the effect of tumor-organoid cell-cell communication on transcriptional programs. RESULTS: ATRT as well as ETMR tumor cells incorporated extensively into the organoid tissue. We observed remarkable differences in the invasiveness of ATRT-MYC cells into TBO in comparison with ATRT-SHH and ETMR cells via high content imaging. Moreover, tumor cells affected the gene expression of different cell types of the organoid by upregulating genes of important signaling/growth related pathways (e. g. MAP2K2, IGFBP2) and epigenetic regulators (like BRD7). Screening through a 300 compound FDA-approved drug library in these TBO, we identified potential innovative therapeutic approaches against these embryonal tumors. CONCLUSION: Tumor-brain-organoids can be used as a platform to study tumor biology, tumor interactions with its neural tissue microenvironment, as well as for high-throughput drug and toxicity screening in pediatric brain tumor precision oncology.

Tissue clearing may alter emission and absorption properties of common fluorophores

In recent years, 3D cell culture has been gaining a more widespread following across many fields of biology. Tissue clearing enables optical analysis of intact 3D samples and investigation of molecular and structural mechanisms by homogenizing the refractive indices of tissues to make them nearly transparent. Here, we describe and quantify that common clearing solutions including benzyl alcohol/benzyl benzoate (BABB), PEG-associated solvent system (PEGASOS), immunolabeling-enabled imaging of solvent-cleared organs (iDISCO), clear, unobstructed brain/body imaging cocktails and computational analysis (CUBIC), and ScaleS4 alter the emission spectra of Alexa Fluor fluorophores and fluorescent dyes. Clearing modifies not only the emitted light intensity but also alters the absorption and emission peaks, at times to several tens of nanometers. The resulting shifts depend on the interplay of solvent, fluorophore, and the presence of cells. For biological applications, this increases the risk for unexpected channel crosstalk, as filter sets are usually not optimized for altered fluorophore emission spectra in clearing solutions. This becomes especially problematic in high throughput/high content campaigns, which often rely on multiband excitation to increase acquisition speed. Consequently, researchers relying on clearing in quantitative multiband excitation experiments should crosscheck their fluorescent signal after clearing in order to inform the proper selection of filter sets and fluorophores for analysis.

Combining Automated Organoid Workflows With Artificial Intelligence-Based Analyses: Opportunities to Build a New Generation of Interdisciplinary High-Throughput Screens for Parkinson's Disease and Beyond

Parkinson's disease (PD) is the second most common neurodegenerative disease and primarily characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain. Despite decades of research and the development of various disease model systems, there is no curative treatment. This could be due to current model systems, including cell culture and animal models, not adequately recapitulating human PD etiology. More complex human disease models, including human midbrain organoids, are maturing technologies that increasingly enable the strategic incorporation of the missing components needed to model PD in vitro. The resulting organoid-based biological complexity provides new opportunities and challenges in data analysis of rich multimodal data sets. Emerging artificial intelligence (AI) capabilities can take advantage of large, broad data sets and even correlate results across disciplines. Current organoid technologies no longer lack the prerequisites for large-scale high-throughput screening (HTS) and can generate complex yet reproducible data suitable for AI-based data mining. We have recently developed a fully scalable and HTS-compatible workflow for the generation, maintenance, and analysis of three-dimensional (3D) microtissues mimicking key characteristics of the human midbrain (called "automated midbrain organoids," AMOs). AMOs build a reproducible, scalable foundation for creating next-generation 3D models of human neural disease that can fuel mechanism-agnostic phenotypic drug discovery in human in vitro PD models and beyond. Here, we explore the opportunities and challenges resulting from the convergence of organoid HTS and AI-driven data analytics and outline potential future avenues toward the discovery of novel mechanisms and drugs in PD research. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Bilateral atypical fractures of the femur: Ten years AFTER ten years of bisphosphonate therapy

Background

Atypical femur fracture (AFF) is a clinically important complication of bisphosphonate (BP) use in the treatment of osteoporosis. The benefits of long-term BP therapy in preventing osteoporotic fractures have been shown to outweigh the risks of treatment. Discontinuation of BPs or "drug holidays" have been implemented as a strategy to reduce the risk of rare complications such as AFF.

Case report

We present the case of a 70-year-old postmenopausal woman who suffered bilateral AFF ten years after discontinuation of BP treatment. Management of this patient included fixation of the complete AFF with an intramedullary rod. A single dose of denosumab was administered prior to referral to endocrinology and seemed to contribute to callus formation. Denosumab was discontinued to prevent progression of the contralateral incomplete AFF. Teriparatide was indicated for the treatment of this patient's osteoporosis and also led to the resolution of the incomplete AFF.

Conclusion

Patients receiving long-term BP therapy should be periodically reevaluated in order to maximize the benefit and minimize the risk of treatment. Current research supports the implementation of drug holidays to decrease the risk of AFF; however, this case report confirms the need for continued monitoring after discontinuation of BP therapy. Additionally, our review of current literature highlights the need for more specific research regarding duration of BP treatment and drug holidays.

Cell-Type-Specific High Throughput Toxicity Testing in Human Midbrain Organoids

Toxicity testing is a crucial step in the development and approval of chemical compounds for human contact and consumption. However, existing model systems often fall short in their prediction of human toxicity in vivo because they may not sufficiently recapitulate human physiology. The complexity of three-dimensional (3D) human organ-like cell culture systems ("organoids") can generate potentially more relevant models of human physiology and disease, including toxicity predictions. However, so far, the inherent biological heterogeneity and cumbersome generation and analysis of organoids has rendered efficient, unbiased, high throughput evaluation of toxic effects in these systems challenging. Recent advances in both standardization and quantitative fluorescent imaging enabled us to dissect the toxicities of compound exposure to separate cellular subpopulations within human organoids at the single-cell level in a framework that is compatible with high throughput approaches. Screening a library of 84 compounds in standardized human automated midbrain organoids (AMOs) generated from two independent cell lines correctly recognized known nigrostriatal toxicants. This approach further identified the flame retardant 3,3',5,5'-tetrabromobisphenol A (TBBPA) as a selective toxicant for dopaminergic neurons in the context of human midbrain-like tissues for the first time. Results were verified with high reproducibility in more detailed dose-response experiments. Further, we demonstrate higher sensitivity in 3D AMOs than in 2D cultures to the known neurotoxic effects of the pesticide lindane. Overall, the automated nature of our workflow is freely scalable and demonstrates the feasibility of quantitatively assessing cell-type-specific toxicity in human organoids in vitro.

Fluorescence-based Single-cell Analysis of Whole-mount-stained and Cleared Microtissues and Organoids for High Throughput Screening

Three-dimensional (3D) cell culture, especially in the form of organ-like microtissues ("organoids"), has emerged as a novel tool potentially mimicking human tissue biology more closely than standard two-dimensional culture. Typically, tissue sectioning is the standard method for immunohistochemical analysis. However, it removes cells from their native niche and can result in the loss of 3D context during analyses. Automated workflows require parallel processing and analysis of hundreds to thousands of samples, and sectioning is mechanically complex, time-intensive, and thus less suited for automated workflows. Here, we present a simple protocol for combined whole-mount immunostaining, tissue-clearing, and optical analysis of large-scale (approx. 1 mm) 3D tissues with single-cell level resolution. While the protocol can be performed manually, it was specifically designed to be compatible with high-throughput applications and automated liquid handling systems. This approach is freely scalable and allows parallel automated processing of large sample numbers in standard labware. We have successfully applied the protocol to human mid- and forebrain organoids, but, in principle, the workflow is suitable for a variety of 3D tissue samples to facilitate the phenotypic discovery of cellular behaviors in 3D cell culture-based high-throughput screens. Graphic abstract: Automatable organoid clearing and high-content analysis workflow and timeline.

Generation and Maintenance of Homogeneous Human Midbrain Organoids

Three-dimensional cell cultures ("organoids") promise to better recapitulate native tissue physiology than traditional 2D cultures and are becoming increasingly interesting for disease modeling and compound screening efforts. While a number of protocols for the generation of neural organoids have been published, most protocols require extensive manual handling and result in heterogeneous aggregates with high sample-to-sample variation, which can hinder screening-based strategies. We have now developed a fast and efficient protocol for the generation and maintenance of highly homogeneous and reproducible midbrain organoids. The protocol is streamlined for use in fully automated workflows but can also be performed manually without the need for highly specialized equipment. It relies on the aggregation of small molecule neural precursor cells (smNPCs) in standard 96-well V-bottomed plates under static culture conditions without cumbersome matrix embedding. The result is ready-to-assay uniform 3D human midbrain organoids available in freely scalable quantities for downstream analyses in 3D cell culture. Graphic abstract: Automated midbrain organoid generation workflow and timeline.

Large Invasive Adrenal Cortical Carcinoma in a Patient With Neurofibromatosis Type I

Background: Adrenal cortical carcinoma is a rare neoplasm. Adrenal cortical carcinoma has previously been reported in less than 10 cases of patients with Neurofibromatosis Type I. Clinical Case: A 44-year-old Hispanic man with Neurofibromatosis Type I (NF1) presented with progressive hypoxia, tachypnea and abdominal pain. Intubation was required with 100% FiO2. CT angiogram of the chest and abdomen showed a 9.5 cm left adrenal mass with tumor thrombus in the left adrenal vein, distal left renal vein, IVC extending into the right atrium, suggestive of an adrenocortical carcinoma. Café-au-spots, neurofibromas and Lisch nodules were seen on physical exam but no signs suggestive of a functional adrenal cortical carcinoma. Transthoracic echocardiogram demonstrated a large well circumscribed echo-dense mass filling the right atrial cavity. Hemodynamically he was unstable with labile blood pressures due to right atrium thrombus burden. He was supported pending pheochromocytoma investigation. Biochemical work up revealed an elevated 24-hour free cortisol concentration of 95.9 ug/d (<=60ug/d) with a normal 24-hour urine metanephrine and normetanephrine [140ug/d (55-320ug/d) and 448 ug/d (114-865ug/d]. Plasma free metanephrine level was normal 0.43 (0.00-0.49nmol/L) and the normetanephrine levels was increased at 2.7 (0.00-0.89nmol/L) consistent with stress response. Serum aldosterone level and renin activity with potassium and DHEA-S levels were normal. Once pheochromocytoma was ruled out, he successfully underwent a left nephrectomy, left adrenalectomy, IVC thrombectomy, right atrium thrombectomy under a multidisciplinary team of surgeons. Surgery was well tolerated and he was discharged home 11 days later. Pathology confirmed adrenal cortical carcinoma, stage 4, with involvement of endocardium and left renal vein with mitotic count greater than 20/50 high-power fields, consistent with a high-grade tumor. Summary: Patients with NF1 have a higher predilection to develop tumors including pheochromocytoma, paraganglioma, gastrointestinal stromal tumor, and pancreatic neuroendocrine tumor. NF1 association with adrenal tumors is well known, most commonly pheochromocytomas which occur in 0.1–5.7% of patients with NF1. However, based on a literature search there have been less than 10 case reports which postulate an association between NF1 and ACC. Genetic analysis of these reported cases suggest a loss of heterozygosity at the NF1 locus as a possible explanation of development of ACC in patients with NF1. Conclusion: Adrenal cortical carcinoma is rare but should be considered in a patient with NF1 and adrenal mass when plasma/urine metanephrines are not suggestive of pheochromocytoma.

Giant Prolactinoma Causing Proptosis and Stroke

Background: Although suprasellar and cavernous sinus invasion are common in giant prolactinomas, intra-orbital extension is extremely uncommon [1]. Even less reported are cases of giant prolactinomas causing cerebral ischemia or death.

Clinical Case: A 51-year old woman presented to the ED with confusion, right-sided weakness and severe left eye proptosis with loss of vision. Five years prior, she underwent a partial transphenoidal resection for a macroprolactinoma due to acute vision changes with compression of the optic chiasm. Prior to surgery, prolactin level was elevated to 2,106 ng/mL (n 2.4-24.0 ng/mL). Post-operative MRI showed residual 2.7 x 3.1 x 2.6 cm mass. Thereafter she was prescribed cabergoline which she self-discontinued three years later. MRI of the brain at time of presentation demonstrated a 10.1 x 6.4 x 4.3 cm sellar/suprasellar mass extending into the left orbit causing severe proptosis and mass effect on the left frontal lobe, temporal lobe, midbrain, and basilar artery with encasement of the left cavernous internal carotid artery. A recent left striatocapsular infarct due to compression of the left middle cerebral artery was present. Prolactin level was elevated to 16,487 ng/mL. Neurosurgery was consulted and recommended medical management. Free thyroxine level was low and thyroid hormone replacement was started. Although the cosyntropin stimulation test showed an appropriate cortisol level peak of 21.5 mcg/dL, she was given stress dose glucocorticoids. Bromocriptine was initially started and titrated and later changed to cabergoline. Six weeks after discharge, she was readmitted with worsening confusion and seizure activity. On day 2 of admission, she decompensated. New hemorrhage inside the mass with increased vasogenic edema and a midline shift was discovered on a head CT. She underwent emergent craniotomy with surgical debulking of the tumor. Unfortunately, her mental status did not improve post-operatively. She was transitioned to hospice care and died 7 days after surgery. Surgical pathology showed a lactotroph adenoma with markedly elevated Ki67 proliferation index of 20-30%.

Conclusion: This case demonstrates an unusually aggressive macroprolactinoma causing severe proptosis, ischemic stroke and death and adds to the very few cases previously reported [2].

References: 1. Karcioglu ZA, Aden LB, Cruz AA, Zaslow L, Saloom RJ. Orbital invasion with prolactinoma: a clinical review of four patients. Ophthalmic Plast Reconstr Surg. 2002 Jan;18(1):64-71. 2. Navarro-Bonnet J, Martínez-Anda JJ, Balderrama-Soto A, Pérez-Reyes SP, Pérez-Neri I, Portocarrero-Ortiz L. Stroke associated with pituitary apoplexy in a giant prolactinoma: a case report. Clin Neurol Neurosurg. 2014 Jan;116:101-3.

Genotype-Phenotype Features of Germline Variants of the TMEM127 Pheochromocytoma Susceptibility Gene: A 10-Year Update

PURPOSE

This work aimed to evaluate genotype-phenotype associations in individuals carrying germline variants of transmembrane protein 127 gene (TMEM127), a poorly known gene that confers susceptibility to pheochromocytoma (PHEO) and paraganglioma (PGL).

DESIGN

Data were collected from a registry of probands with TMEM127 variants, published reports, and public databases.

MAIN OUTCOME ANALYSIS

Clinical, genetic, and functional associations were determined.

RESULTS

The cohort comprised 110 index patients (111 variants) with a mean age of 45 years (range, 21-84 years). Females were predominant (76 vs 34, P < .001). Most patients had PHEO (n = 94; 85.5%), although PGL (n = 10; 9%) and renal cell carcinoma (RCC, n = 6; 5.4%) were also detected, either alone or in combination with PHEO. One-third of the cases had multiple tumors, and known family history was reported in 15.4%. Metastatic PHEO/PGL was rare (2.8%). Epinephrine alone, or combined with norepinephrine, accounted for 82% of the catecholamine profiles of PHEO/PGLs. Most variants (n = 63) occurred only once and 13 were recurrent (2-12 times). Although nontruncating variants were less frequent than truncating changes overall, they were predominant in non-PHEO clinical presentations (36% PHEO-only vs 69% other, P < .001) and clustered disproportionately within transmembrane regions (P < .01), underscoring the relevance of these domains for TMEM127 function. Integration of clinical and previous experimental data supported classification of variants into 4 groups based on mutation type, localization, and predicted disruption.

CONCLUSIONS

Patients with TMEM127 variants often resemble sporadic nonmetastatic PHEOs. PGL and RCC may also co-occur, although their causal link requires further evaluation. We propose a new classification to predict variant pathogenicity and assist with carrier surveillance.

Permissive epigenomes endow reprogramming competence to transcriptional regulators

Identifying molecular and cellular processes that regulate reprogramming competence of transcription factors broadens our understanding of reprogramming mechanisms. In the present study, by a chemical screen targeting major epigenetic pathways in human reprogramming, we discovered that inhibiting specific epigenetic roadblocks including disruptor of telomeric silencing 1-like (DOT1L)-mediated H3K79/K27 methylation, but also other epigenetic pathways, catalyzed by lysine-specific histone demethylase 1A, DNA methyltransferases and histone deacetylases, allows induced pluripotent stem cell generation with almost all OCT factors. We found that simultaneous inhibition of these pathways not only dramatically enhances reprogramming competence of most OCT factors, but in fact enables dismantling of species-dependent reprogramming competence of OCT6, NR5A1, NR5A2, TET1 and GATA3. Harnessing these induced permissive epigenetic states, we performed an additional screen with 98 candidate genes. Thereby, we identified 25 transcriptional regulators (OTX2, SIX3, and so on) that can functionally replace OCT4 in inducing pluripotency. Our findings provide a conceptual framework for understanding how transcription factors elicit reprogramming in dependency of the donor cell epigenome that differs across species.

The Use of FRAX in Identifying Women Less Than 65 Years Needing Bone Mineral Density Testing

The purpose of this study is to determine if the United States Preventive Services Task Force (USPSTF) screening guideline for osteoporosis identifies women under the age of 65 with osteoporosis needing bone mineral density (BMD) testing. If the Fracture Risk Assessment Tool (FRAX) tool fails to identify women under the age of 65 with undiagnosed osteoporosis, then diagnosis and treatment are delayed, potentially leading to increased fractures and morbidity. Another aim of this study is to characterize women under the age of 65 with osteoporosis that FRAX fails to identify and provide descriptive data on our study population. A retrospective chart review was completed between 2012 and 2018. We extracted data for 113 women ≤ 65-years with osteoporosis confirmed by BMD or fractures. Major osteoporotic fracture (MOF) risk calculation without BMD by FRAX of 9.3% or greater (high risk group) was found in 51 (45.1%) of patients. Osteoporosis by T-score < 2.5 was evident in 102 (90%) of patients. Previous osteoporotic fractures were noted in 29 (25.7%) of patients. The average age of women in the high-risk group was 58 years and 55 years in the low-risk group. The sensitivity of FRAX for identifying women with a T-score <-2.5 was 40%. The sensitivity of FRAX for identifying women with a history of fracture was 32%. The sensitivity of FRAX for identifying women with a T-score <-2.5 or identifying women with a history of fracture was 32%. These results demonstrate that the FRAX tool alone (USPSTF recommendation) fails to identify many women under the age of 65 with osteoporosis in need of BMD testing. Over half of women would not have had a BMD performed based on guidelines for screening BMD in women <65. Further study is needed to characterize women under the age of 65 with osteoporosis with a FRAX MOF risk less than 9.3%.

A fully automated high-throughput workflow for 3D-based chemical screening in human midbrain organoids

Three-dimensional (3D) culture systems have fueled hopes to bring about the next generation of more physiologically relevant high-throughput screens (HTS). However, current protocols yield either complex but highly heterogeneous aggregates (‘organoids’) or 3D structures with less physiological relevance (‘spheroids’). Here, we present a scalable, HTS-compatible workflow for the automated generation, maintenance, and optical analysis of human midbrain organoids in standard 96-well-plates. The resulting organoids possess a highly homogeneous morphology, size, global gene expression, cellular composition, and structure. They present significant features of the human midbrain and display spontaneous aggregate-wide synchronized neural activity. By automating the entire workflow from generation to analysis, we enhance the intra- and inter-batch reproducibility as demonstrated via RNA sequencing and quantitative whole mount high-content imaging. This allows assessing drug effects at the single-cell level within a complex 3D cell environment in a fully automated HTS workflow.

In 1907, the American zoologist Ross Granville Harrison developed the first technique to artificially grow animal cells outside the body in a liquid medium. Cells are still grown in much the same way in modern laboratories: a single layer of cells is placed in a warm incubator with nutrient-rich broth. These cell layers are often used to test new drugs, but they cannot recapitulate the complexity of a real organ made from multiple cell types within a living, breathing human body.

Growing three-dimensional miniature organs or 'organoids' that behave in a similar way to real organs is the next step towards creating better platforms for drug screening, but there are several difficulties inherent to this process. For one thing, it is hard to recreate the multitude of cell types that make up an organ. For another, the cells that do grow often fail to connect and communicate with each other in biologically realistic ways. It is also tough to grow a large number of organoids that all behave in the same way, making it hard to know whether a particular drug works or whether it is just being tested on a 'good' organoid.

Renner et al. have been able to overcome these issues by using robotic technology to create thousands of identical, mid-brain organoids from human cells in the lab. The robots perform a series of precisely controlled tasks – including dispensing the initial cells into wells, feeding organoids as they grow and testing them at different stages of development. These mini-brains, which are the size of the head of a pin, mimic the part of the brain where Parkinson's disease first manifests. They can be used to test new drugs for Parkinson's, and to better understand the biology of the brain. Perhaps more importantly, other types of organoids can be created using the same technique to model diseases that affect other areas of the brain, or other organs altogether. For example, Renner et al. also generated forebrain organoids using an automated approach for both generation and analysis.

This research, which shows that organoids can be grown and tested in a fully automated, reproducible and scalable way, creates a platform to quickly, cheaply and easily test thousands of drugs for Parkinson's and other difficult-to-treat diseases in a human setting. This approach has the potential to reduce research waste by increasing the chances that a drug that works in the lab will also ultimately work in a patient; and reduce animal experiments, as drugs that do not work in human tissues will not proceed to animal testing.

MON-925 A Wolf in Sheep’s Clothing: Intermittent Hypercalcemia from an Intrathyroidal Parathyroid Carcinoma

Parathyroid carcinomas have an estimated prevalence of <0.1% of all cancers and is found in <1% of patients with primary hyperparathyroidism (PHPT). While they frequently present with PTH- mediated hypercalcemia, they are often distinguished by severe hypercalcemia and markedly elevated PTH levels compared to their benign counterparts. Parathyroid cancers most often arise from existing parathyroid glands, making them identifiable with standard imaging modalities such as parathyroid sestamibi scan, thyroid ultrasound, and 4-D CT scan. There are reports of non-functioning parathyroid carcinomas, including those that are intrathyroidal. Most of the reported cases are found de novo. We present a case of an intrathyroidal parathyroid carcinoma with intermittent hypercalcemia. A 72-year-old man with a history of Graves’ disease and RAI ablation in the 1970’s was found to have hypercalcemia up to 14.1 mg/dL (8.5 - 10.1) with a PTH level of 223 pg/mL (14 - 64). He denied any constipation, bone pain, fractures, renal stones, or changes in mental status. Thyroid ultrasound demonstrated a 3.9 cm R lobe complex nodule reported as TI-RADS 4, and a hypoechoic 1.0 cm nodule in the L lobe. No definitive parathyroid adenoma was reported. A parathyroid sestamibi scan showed persistent uptake in area of the L 1.0 cm nodule favoring a PTH adenoma while the R nodule had initial radiotracer uptake with delayed washout but no technetium uptake. Laboratory evaluation demonstrated a 24-hour urinary calcium of 338 mg/24hr, low 25-OH vitamin D, and normal vitamin D 1,25 levels. Osteoporosis was diagnosed by BMD with T-score of -3.2 at the femoral neck. Repeat serum corrected calcium level was 9.7 mg/dL and PTH was 93 pg/mL. FNA cytology of the R thyroid mass was reported as benign thyroid tissue. Due to size of the R thyroid nodule, the patient underwent a R hemithyroidectomy with L parathyroidectomy. Intraoperative PTH levels decreased from 154 to 120 pg/mL after removal of L parathyroid adenoma; PTH level decreased further to 12.9 pg/mL after R hemithyroidectomy. Surgical pathology revealed 4.5 cm R parathyroid carcinoma without thyroid tissue with positive margins, and a hypercellular L parathyroid gland. PHPT resolved. After review of all aspects of the case and discussion with patient, the decision was made to monitor his calcium and PTH levels and repeat BMD 1 year from resection. This is an uncommon presentation of a rare endocrine malignancy. To our knowledge, there are few case reports of non-functional parathyroid carcinomas that were initially reported as thyroid cancer or benign thyroid tissue after biopsy. This report underscores the importance in keeping this rare diagnosis in the evaluation of PTH-mediated hypercalcemia.

SAT-183 Right Adrenal Mass: An Unusual Presentation

Background: Adrenal masses may be incidentally found on imaging done for other reasons. The prevalence is 4.4% and up to 10% in older patients. Malignancy is an uncommon cause in patients without a known diagnosis of cancer. The frequency of primary adrenal carcinoma in patients with adrenal incidentalomas is approximately 2.0 to 5.0%; another 0.7 to 2.5% have non-adrenal metastases to the adrenal gland.

Clinical Case: 54-year-old man with Hepatitis C, prior alcohol abuse, and cirrhosis was found to have an increase in the alpha-fetoprotein (AFP) level from normal to 244 ng/ml (nl<15.1) over a 6-month period. Liver MRI was consistent with a cirrhotic liver without focal enhancing lesions and showed a new indeterminate 7.6 cm right retroperitoneal lesion arising from the adrenal gland compared to a prior CT of the abdomen a year early. Further imaging confirmed a 9.6 x 9 x 7.6 cm heterogeneously enhancing right adrenal lesion with a necrotic center, concerning for a primary malignancy; up to 11.1cm a month later. Patient referred to Endocrine for further evaluation. There were no symptoms suggestive of Cushing’s, pheochromocytoma or primary hyperaldosteronism. On exam there were no hypertension, dorsal fat pad, supraclavicular fullness, skin thinning or purplish striae. Biochemical workup was consistent with a non-functioning adrenal mass. DHEA-S was 11 (38-313 mcg/dl). CT-guided core needle biopsy of right adrenal gland was consistent with metastatic hepatocellular carcinoma. CT pelvis with contrast re-demonstrated the right adrenal mass now measuring 11.4 x 10 x 10 cm with new enlarged retrocaval lymph node and no focal arterially enhancing lesions. During embolization of adrenal lesion/ hepatic angiogram, multiple liver lesions not previously identified were reported with the largest of 2.9cm size and enhancing lesions in the sacrum and bilateral iliac bones; decrease in size of the necrotic right adrenal mass measuring 8.2 x 9.1 x 9.1 cm 1-month post-embolization. Patient following with Oncology.

Conclusion:Unilateral isolated adrenal metastasis from occult hepatocellular carcinoma (HCC) is extremely rare. Adrenal gland is the second most common site of hematogenous spread from HCC after the lung and has been found in up to 8.4% of cases at autopsy. In our case, the adrenal metastasis was the first clinical presentation of HCC with no evident hepatic lesion until 9 months of adrenal finding; few cases have been reported. Fine needle aspiration/needle biopsy of suspected malignancy is useful to detect primary tumor in case of metastatic disease that is silent at this stage. Adrenal metastasis in HCC are seldom treated by surgery as by the time of diagnosis the tumor is usually far advanced and/or patients are poor surgical candidates. This case highlights the importance of suspecting underlying HCC in isolated adrenal mass in a patient with high risk factors.

The Convergence of Stem Cell Technologies and Phenotypic Drug Discovery

Recent advances in induced pluripotent stem cell technologies and phenotypic screening shape the future of bioactive small-molecule discovery. In this review we analyze the impact of small-molecule phenotypic screens on drug discovery as well as on the investigation of human development and disease biology. We further examine the role of 3D spheroid/organoid structures, microfluidic systems, and miniaturized on-a-chip systems for future discovery strategies. In highlighting representative examples, we analyze how recent achievements can translate into future therapies. Finally, we discuss remaining challenges that need to be overcome for the adaptation of the next generation of screening approaches.

Abnormal bone mineral content and density in people with tetrasomy 18p

Tetrasomy 18p is a rare chromosomal abnormality, resulting from an additional iso-chromosome composed of two copies of the short arm. It is characterized by craniofacial abnormalities, neuromuscular dysfunction, and developmental delay. The Chromosome 18 Clinical Research Center has established the largest cohort of individuals with this rare genetic condition. Here, we describe a case series of 21 individuals with tetrasomy 18p who have a previously unreported clinical finding: low bone mineral density. Most individuals met criteria for low bone density despite being relatively young (mean age of 21 years). Clinicians providing care to individuals affected by Tetrasomy 18p should be aware of their increased risk for decreased bone density and pathological fractures.

Chronic Myeloid Leukemia Associated Hypercalcemia: A Case Report and Literature Review

Patient: Male, 58

Final Diagnosis: Hypercalcemia

Symptoms: Confusion • dehydration

Medication: —

Clinical Procedure: —

Specialty: Endocrinology and Metabolism

Derivation and expansion using only small molecules of human neural progenitors for neurodegenerative disease modeling

Phenotypic drug discovery requires billions of cells for high-throughput screening (HTS) campaigns. Because up to several million different small molecules will be tested in a single HTS campaign, even small variability within the cell populations for screening could easily invalidate an entire campaign. Neurodegenerative assays are particularly challenging because neurons are post-mitotic and cannot be expanded for implementation in HTS. Therefore, HTS for neuroprotective compounds requires a cell type that is robustly expandable and able to differentiate into all of the neuronal subtypes involved in disease pathogenesis. Here, we report the derivation and propagation using only small molecules of human neural progenitor cells (small molecule neural precursor cells; smNPCs). smNPCs are robust, exhibit immortal expansion, and do not require cumbersome manual culture and selection steps. We demonstrate that smNPCs have the potential to clonally and efficiently differentiate into neural tube lineages, including motor neurons (MNs) and midbrain dopaminergic neurons (mDANs) as well as neural crest lineages, including peripheral neurons and mesenchymal cells. These properties are so far only matched by pluripotent stem cells. Finally, to demonstrate the usefulness of smNPCs we show that mDANs differentiated from smNPCs with LRRK2 G2019S are more susceptible to apoptosis in the presence of oxidative stress compared to wild-type. Therefore, smNPCs are a powerful biological tool with properties that are optimal for large-scale disease modeling, phenotypic screening, and studies of early human development.

Oral administration of biochemically active microcapsules to treat uremia: new insights into an old approach

This paper begins with an extensive review of previous research on the degradation of non-protein nitrogen compounds for improved therapy of renal failure. During the 1970s, Malchesky established that naturally occurring strains of microorganisms were highly effective for the in vitro degradation of urea and other compounds found in urine, and that these bacteria could be conditioned with selected media to enhance growth and degradation efficiency. A few years later, Setala introduced the concept of oral delivery of lyophilized bacteria, harvested from soil, to uremic patients, for degradation of non-protein nitrogen compounds. In the 1990s, Chang proposed delivery of encapsulated genetically modified bacteria for removal of uremic waste products in vitro and in vivo. Recently, our group has pursued the idea of orally delivering formulated combinations of enzymes or modified bacteria. A new study is also described, which characterizes the capacity of a single alginate microcapsule containing a mixture of genetically modified cells and enzyme to degrade urea, uric acid and creatinine. The combination capsules were found to be effective in vitro and in vivo in a rodent model of chemically-induced renal failure. Reduction of urea concentration in vivo required co-administration of a cation exchange resin to adsorb ammonia. Increased investigative effort is warranted for these approaches which offer significant potential as an adjunct to conventional forms of dialysis.

Biomimetic materials replicating Schwann cell topography enhance neuronal adhesion and neurite alignment in vitro

It is well established that Schwann cells (SCs) promote and enhance axon guidance and nerve regeneration by providing multiple cues, including extracellular matrix, cell surface molecules, neurotrophic factors and cellular topography. Which of the elements of the complex environment associated with SCs provides the essential information for directed nerve growth is unclear, because, until now, it has been impossible to investigate their contributions individually. Our development of biomimetic materials that replicate the micro- and nanoscale topography of SCs has allowed us to investigate for the first time the role of cellular topography in directing nerve growth. Dorsal root ganglion (DRG) neurons were cultured on flat poly(dimethyl siloxane) (PDMS) and on PDMS replicas with protruding SC topography. Image analysis showed that more neurons adhered to the replicas than to the flat substrates, and that neurite growth on the replicas followed the underlying SC pattern. Neuronal alignment was dependent on cell density. Live SCs derived from the DRG also grew along the replica SC pattern. These results suggest that the combination of micro- and nanoscale topographical cues provided by SCs can influence nerve growth and point toward design parameters for future nerve guidance channels.

Rate of bone loss is greater in young Mexican American men than women: the San Antonio Family Osteoporosis Study

Little is known about the progression of bone loss during young adulthood and whether it differs between men and women. As part of the San Antonio Family Osteoporosis Study we tested whether bone mineral density (BMD) changed over time in men or women, and whether the rate of BMD change differed between the sexes. BMD of the proximal femur, spine, radius, and whole body was measured in 115 men and 202 pre-menopausal women (ages 25 to 45 years; Mexican American ancestry) by dual-energy x-ray absorptiometry at two time points (5.6 years apart), from which annual percent change-in-BMD was calculated. Likelihood-based methods were used to test whether change-in-BMD differs from zero or differs between men and women. In men, percent change-in-BMD was significantly greater than zero for the 1/3 radius (i.e. indicating a gain of BMD; Bonferroni-adjusted p<0.01), less than zero for the femoral neck, lumbar spine, ultradistal radius, and whole body (i.e. indicating a loss of BMD; p<0.01 for all), and not different than zero for the total hip (p=0.24). In women, percent change-in-BMD was greater than zero for the total hip, 1/3 radius, and whole body (p<0.01 for all), less than zero for the ultradistal radius (p<0.01), and not significantly different than zero for the femoral neck and lumbar spine (p=1.0 for both). For all skeletal sites, men experienced greater decrease in BMD (or less increase in BMD) than women; this result was observed both with and without adjustment for age, BMI, and change-in-BMI (p<0.05 for all). These results suggest that significant bone loss occurs at some skeletal sites in young men and women, and that loss of BMD is occurring significantly faster, or gain of BMD is occurring significantly slower, in young men compared to young women.

Quantitative trait locus on chromosome 1q influences bone loss in young Mexican American adults

Bone loss occurs as early as the third decade and its cumulative effect throughout adulthood may impact risk for osteoporosis in later life, however, the genes and environmental factors influencing early bone loss are largely unknown. We investigated the role of genes in the change in bone mineral density (BMD) in participants in the San Antonio Family Osteoporosis Study. BMD change in 327 Mexican Americans (ages 25-45 years) from 32 extended pedigrees was calculated from DXA measurements at baseline and follow-up (3.5 to 8.9 years later). Family-based likelihood methods were used to estimate heritability (h(2)) and perform autosome-wide linkage analysis for BMD change of the proximal femur and forearm and to estimate heritability for BMD change of lumbar spine. BMD change was significantly heritable for total hip, ultradistal radius, and 33% radius (h(2) = 0.34, 0.34, and 0.27, respectively; p < 0.03 for all), modestly heritable for femoral neck (h(2) = 0.22; p = 0.06) and not heritable for spine BMD. Covariates associated with BMD change included age, sex, baseline BMD, menopause, body mass index, and interim BMI change, and accounted for 6% to 24% of phenotype variation. A significant quantitative trait locus (LOD = 3.6) for femoral neck BMD change was observed on chromosome 1q23. In conclusion, we observed that change in BMD in young adults is heritable and performed one of the first linkage studies for BMD change. Linkage to chromosome 1q23 suggests that this region may harbor one or more genes involved in regulating early BMD change of the femoral neck.

Genetic influences on bone loss in the San Antonio Family Osteoporosis study

The genetic contribution to age-related bone loss is not well understood. We estimated that genes accounted for 25-45% of variation in 5-year change in bone mineral density in men and women. An autosome-wide linkage scan yielded no significant evidence for chromosomal regions implicated in bone loss.

INTRODUCTION

The contribution of genetics to acquisition of peak bone mass is well documented, but little is known about the influence of genes on subsequent bone loss with age. We therefore measured 5-year change in bone mineral density (BMD) in 300 Mexican Americans (>45 years of age) from the San Antonio Family Osteoporosis Study to identify genetic factors influencing bone loss.

METHODS

Annualized change in BMD was calculated from measurements taken 5.5 years apart. Heritability (h(2)) of BMD change was estimated using variance components methods and autosome-wide linkage analysis was carried out using 460 microsatellite markers at a mean 7.6 cM interval density.

RESULTS

Rate of BMD change was heritable at the forearm (h(2) = 0.31, p = 0.021), hip (h(2) = 0.44, p = 0.017), spine (h(2) = 0.42, p = 0.005), but not whole body (h(2) = 0.18, p = 0.123). Covariates associated with rapid bone loss (advanced age, baseline BMD, female sex, low baseline weight, postmenopausal status, and interim weight loss) accounted for 10% to 28% of trait variation. No significant evidence of linkage was observed at any skeletal site.

CONCLUSIONS

This is one of the first studies to report significant heritability of BMD change for weight-bearing and non-weight-bearing bones in an unselected population and the first linkage scan for change in BMD.

Sequestosome 1 (SQSTM1) mutations in Paget's disease of bone from the United States

Paget's disease of bone (PDB) is a localized bone disease characterized by excessive bone resorption due to overactive osteoclasts. Seven genetic loci (PDB1-PDB7) have been reported for late-onset PDB. PDB3 is the only locus where a gene, sequestosome 1 (SQSTM1), has been identified. Mutations in SQSTM1 have been associated with both sporadic and hereditary PDB in different populations. However, the SQSTM1 mutation frequency in PDB patients from a more heterogeneous population has never been reported. To investigate this, we determined the frequency of mutations in patients from the United States. Blood was collected from sporadic and hereditary PDB patients in the United States. DNA was isolated from whole blood or from serum. The SQSTM1 sequence was determined for exons and intron/exon junctions from whole blood and serum. A total of 112 (39 hereditary, 73 sporadic) samples were collected. Eight mutations were found in hereditary PDB patients, for a mutation frequency of 20.5% (95% confidence interval [CI] 10.8-35.5%) and did not differ significantly from mutation rates observed in studies in Canada, Great Britain, and The Netherlands. No mutations were found in sporadic patients, for a frequency of 0% (95% CI 0.0-5.0%), which was statistically significantly lower than the mutation rates previously observed in populations from Australia (P = 0.009), Canada (P = 0.008), Great Britain (P = 0.02), and France (P = 0.04) but not compared to rates from Belgium, The Netherlands, and Italy. Four out of five families with the P392L mutation carried it on the H2 haplotype. Mutations in SQSTM1 seem to contribute to the pathogenesis of PDB in hereditary, but not sporadic, patients in the United States.

Gonadotropin-releasing hormone agonist-induced pituitary apoplexy in treatment of prostate cancer: case report and review of literature

OBJECTIVE

To describe a case and review the literature on the rare complication of pituitary apoplexy after administration of a gonadotropin-releasing hormone agonist (GnRHa) for treatment of patients with prostate cancer.

METHODS

We present a detailed case report of a patient with immediate signs of pituitary apoplexy after receiving a GnRHa and review the 6 previously reported cases in the literature. A 60-year-old man presented to a local hospital with severe headache, nausea, vomiting, and diplopia. Prostate cancer had recently been diagnosed, and he had received his first dose of a GnRHa 4 hours before this presentation. On physical examination, he was confused and had ptosis of the left eye. A head computed tomographic scan without contrast enhancement showed soft tissue filling the sella, without intracranial hemorrhage or mass effect. He was discharged with the diagnosis of viral meningitis. Three weeks later, he presented again with severe headache and diplopia. He had confusion, lethargy, disorientation, a blood pressure of 88/64 mm Hg, and left cranial nerve III, IV, and VI paralysis. Magnetic resonance imaging of the brain revealed an enhancing pituitary mass with hemorrhage extending to the optic chiasm, consistent with pituitary apoplexy. Laboratory results were consistent with panhypopituitarism. Surgical excision revealed a necrotic pituitary macroadenoma with hemorrhage. Tumor immunohistochemical staining was positive only for luteinizing hormone.

CONCLUSION

We describe a rare adverse effect of GnRHa therapy, which unmasked a gonadotropin-secreting pituitary macroadenoma. This case adds to the 6 previously reported cases of GnRHa administration inducing pituitary apoplexy in men with prostate cancer.

Decreased bone mineral density is correlated with increased subclinical atherosclerosis in older, but not younger, Mexican American women and men: the San Antonio Family Osteoporosis Study

An association has been reported between cardiovascular disease (CVD) and osteoporosis, perhaps attributable to the presence of common risk factors. To assess this possibility, we measured areal bone mineral density (BMD) and carotid artery intimal medial thickness (IMT), a measure of preclinical atherosclerosis, in 535 women and 335 men from the San Antonio Family Osteoporosis Study. Variance decomposition methods were used to determine whether cross-sectional measures of areal BMD (measured by dual-energy X-ray absorptiometry) of the total hip, spine, and forearm were correlated with IMT, serum lipids, and/or C-reactive protein (CRP), a marker of inflammation, after accounting for known environmental factors. We observed significant inverse correlations of IMT and BMD at all bone sites in women >60 years of age (P < 0.001) and modest positive correlations (not significant) of IMT on hip BMD (P < 0.1) in women <60 years of age. Similarly, we observed negative correlations between IMT and forearm BMD in men >60 years of age (P < 0.001) and positive correlations in men <60 years of age (P = 0.05). Variation in risk factors for CVD, including serum levels of low- and high-density lipoprotein cholesterol, low-density lipoprotein particle size, triglycerides, paraoxonase 1 activity, and CRP did not account for the relationship between BMD and IMT in either older or younger men or women. In summary, our results demonstrate that decreased BMD is correlated with increased IMT in older (but not younger) Mexican American men and women, independent of serum CVD risk factors.

Effects of alendronate on bone mineral density in men with prostate cancer treated with androgen deprivation therapy

Bone mineral density (BMD) is low in men with prostate cancer treated with androgen deprivation therapy (ADT). Intravenous bisphosphonates have been shown to prevent the bone loss, however, the effectiveness of oral bisphosphonates have not been studied in this population. In this retrospective cohort study, we examine the effect of alendronate on BMD in men with prostate cancer receiving ADT. We reviewed the charts of patients receiving ADT referred from the VA Urology Clinic for BMD measurements. Forty seven patients had follow up BMD measurements (17.6+8.3 months). Twenty-two men (47%) were also receiving alendronate 70 mg every week. There was a statistically significant difference (p<0.05) in the percent change of BMD per year at the spine (-1.29+/-0.7% vs. +1.41+/-0.7%), total hip (-0.94+/-0.6% vs. +0.97+/-0.5%), femoral neck (-2.17+/-0.7% vs. +0.32+/-0.6%) and trochanter (-2.01+/-0.7% vs. +0.79+/-0.8%) in the patients not treated compared to those treated with alendronate. In the four other measured sites at the radius (proximal, mid, ultra distal and total), there were no statistically significant differences (p>0.05). These findings confirm that bone loss occurs in men receiving ADT at all sites measured. The use of alendronate prevents bone loss at the spine and hip, but does not seem to have the same protective effect at the radius.

Fabrication of polymeric replicas of cell surfaces with nanoscale resolution

We report an approach for fabricating biomimetic surface replicas of cells with nanoscale resolution. Fixed cells serve as a template for a two-stage replica molding process. Cast from the template, the impression replica contains a reproduction of cellular topographical features indented into its surface, and cast from the impression replica, the relief replica contains a copy of these features protruding from its surface. Various polymers and cells can be utilized, and scanning electron microscopy, atomic force microscopy, and white light interferometry analyses confirm the replication of nanoscale features. These replicas are useful for investigating cellular function and for biomimetic tissue engineering.

Upregulation of TGF-β1 Expression May Be Necessary but Is Not Sufficient for Excessive Scarring

Transforming growth factor beta 1 (TGF-beta1) upregulation has been implicated in hypertrophic scars and keloids, but it is unclear if it is the cause or an effect of excessive scar formation. In this study, we overexpressed TGF-beta1 in fibroblasts and characterized its role. Normal human dermal fibroblasts were genetically modified to overexpress TGF-beta1 as the wild-type latent molecule or as a mutant constitutively active molecule. TGF-beta1 secretion was measured, as were the effects of TGF-beta1 upregulation on cell proliferation, expression of smooth muscle cell alpha actin (SMC alpha-actin) and ability to contract collagen lattices. Fibroblasts were implanted intradermally into athymic mice and tissue formation was analyzed over time by histology and immunostaining. Gene-modified fibroblasts secreted approximately 20 times the TGF-beta1 released by control cells, but only cells expressing mutant TGF-beta1 secreted it in the active form. Fibroblasts expressing the active TGF-beta1 gene had increased levels of SMC alpha-actin and enhanced ability to contract a collagen lattice. After intradermal injection into athymic mice, only fibroblasts expressing active TGF-beta1 formed "keloid-like" nodules containing collagen, which persisted longer than implants of the other cell types. We conclude that upregulation of TGF-beta1 by fibroblasts may be necessary, but is not sufficient for excessive scarring. Needed are other signals to activate TGF-beta1 and prolong cell persistence.

Prevalence of osteopenia and osteoporosis by central and peripheral bone mineral density in men with prostate cancer during androgen-deprivation therapy

OBJECTIVES

To determine the prevalence of osteopenia and osteoporosis by central (spine and hip) and peripheral (radius) bone mineral density (BMD) in men with prostate cancer undergoing androgen-deprivation therapy (ADT). Low BMD and fractures are prevalent in this group of men. Most published studies on ADT-related bone loss have documented the loss of BMD in the spine and hip as measured by dual x-ray absorptiometry. In one study, the loss of BMD was most pronounced at the radius.

METHODS

In a chart review of patients receiving ADT, the spine and hip BMD results were recorded in 89 patients. Of these 89 patients, the BMD of the radius was also recorded in 53.

RESULTS

In the 89 patients with BMD measurements of the spine and hip, 24 (26.9%) had osteoporosis of the hip or spine as defined by a T score of -2.5 or less, and 45 patients (50.6%) had osteopenia (T score -1.0 to -2.5). In the subset of 53 patients who also had the BMD of the radius measured, the results of the BMD of the radius changed the category of diagnosis in 18 patients (34%). The prevalence of osteoporosis increased from 25% to 53% when the results of the radius were included.

CONCLUSIONS

Men with prostate cancer treated with ADT have a high prevalence of osteopenia and osteoporosis as determined by peripheral and central BMD measurements. The use of the peripheral BMD measurement appears to identify more patients with osteoporosis and suggests its use in the evaluation of osteoporosis in men receiving ADT.

Neurite bridging across micropatterned grooves

After injury, regenerating axons must navigate complex, three-dimensional (3D) microenvironments. Topographic guidance of neurite outgrowth has been demonstrated in vitro with culture substrates that contain micropatterned features on the nanometer-micron scale. In this study we report the ability of microfabricated biomaterials to support neurite extension across micropatterned grooves with feature sizes on the order of tens of microns, sizes relevant to the design of biomaterials and tissue engineering scaffolds. Neonatal rat dorsal root ganglion (DRG) neurons were cultured on grooved substrates of poly(dimethyl siloxane) coated with poly-L-lysine and laminin. Here we describe an unusual capability of a subpopulation of DRG neurons to extend neurites that spanned across the grooves, with no underlying solid support. Multiple parameters influenced the formation of bridging neurites, with the highest numbers of bridges observed under the following experimental conditions: cell density of 125,000 cells per sample, groove depth of 50 microm, groove width of 30 microm, and plateau width of 200 microm. Bridges were formed as neurites extended from a neuron in a groove, contacted adjacent plateaus, pulled the neuron up to become suspended over the groove, and the soma translocated to the plateau. These studies are of interest to understanding cytoskeletal dynamics and designing biomaterials for 3D axon guidance.

Urinary calcium excretion in primary hyperparathyroidism: relationship to 25-hydroxyvitamin d status

OBJECTIVE

To determine the prevalence of vitamin D deficiency in patients with primary hyperparathyroidism (PHPT) and evaluate the relationship between urinary calcium excretion and serum 25-hydroxyvitamin D (25-OH-D) levels in patients with PHPT.

METHODS

We present a case report and a review of the medical records of patients with PHPT. Of 75 patients with PHPT substantiated by hypercalcemia and increased levels of intact parathyroid hormone (iPTH), 35 were identified with laboratory evaluation of vitamin D levels and 24-hour urinary calcium excretion. These study subjects were stratified as 25-OH-D deficient, insufficient, or replete (on the basis of serum values of <15, 15 to 25, or >25 ng/mL, respectively). Total 24-hour urinary calcium excretion and the fractional excretion of calcium (FECa) were analyzed as a function of 25-OH-D status.

RESULTS

Of the 35 study subjects, 14 (40%) and 13 (37%) had 25-OH-D deficiency or insufficiency, respectively. Those patients with a 25-OH-D level <15 ng/mL had higher serum iPTH concentrations as well as lower urinary calcium excretion and FECa. No significant correlations were found, however, between 25-OH-D status and iPTH concentrations (r = -0.21; P = 0.23), total 24-hour urinary calcium excretion (r = 0.07; P = 0.7), or FECa (r = 0.04; P = 0.8).

CONCLUSION

Vitamin D deficiency (25-OH-D levels <15 ng/mL) was common in our population of patients with PHPT. Urinary calcium excretion was not significantly altered by 25-OH-D deficiency in patients with newly recognized PHPT. Measurements of total urinary calcium excretion and FECa can be reliably used to rule out familial benign hypocalciuric hypercalcemia in the initial evaluation of PHPT, regardless of 25-OH-D status. Determining 25-OH-D concentrations best assesses the vitamin D status.

In Vivoandin VitroDegradation of Urea and Uric Acid by Encapsulated Genetically Modified Microorganisms

This study was undertaken to characterize the capacity of a combination of genetically modified bacteria to lower elevated levels of urea and uric acid and thus to serve as a potential adjunct to maintenance dialysis in patients with chronic renal failure. Two strains of genetically modified bacteria expressing enzymes, urease to degrade urea and uricase to degrade uric acid, were identified, combined, and dispersed in 600-microm alginate microcapsules suitable for oral administration. In 24 h in vitro experiments, 5 mL of these capsules completely cleared 95% of the urea and >99% of the uric acid from 100 mL of a challenge solution formulated to the concentration of these solutes in a presenting hemodialysis patient. The process of urea degradation was found to be intracellular and each bacterial strain was specific for its substrate. Solute degradation in vivo was evaluated with a chemically induced model of acute renal failure, using Sprague-Dawley rats. Orally administered capsules were found to remain in the gastrointestinal tract for at least 6 h. The severity of azotemia and hyperuricaemia after chemical induction of acute renal failure was reduced by 64 and 31%, respectively, on administration of the capsules. Reduction of urea concentration (but not uric acid concentration) in vivo required coadministration of an ion-exchange resin to adsorb ammonia. Oral delivery of a combination of genetically modified microorganisms should be further explored in chronic renal failure models as a useful adjunct to dialysis or to immunosorption for the treatment of uremia.

Degradation of Low Molecular Weight Uremic Solutes by Oral Delivery of Encapsulated Enzymes

An alginate microcapsule was developed that contains three enzymes (urease, uricase, and creatininase) capable of effectively degrading urea, uric acid, and creatinine, which are elevated to pathologic levels in patients with kidney failure. The capsules were evaluated in vitro and in vivo in a rodent model and evidenced considerable potential as a possible adjunctive therapy in the treatment of ESRD. In vitro, 5 mL of the capsules incorporating a quantity of enzymes in the mg range effectively degraded all the uric acid, 97% of the urea, and 70% of the creatinine within 24 hours in a 100 mL test solution simulating the concentration of these solutes in uremic plasma. Enzyme degradation of urea followed Michaelis-Menten kinetics, and the Lineweaver-Burk plots for both encapsulated enzymes and unencapsulated control animals were superimposable, indicating that mass transfer through the capsules was not rate limiting in the degradation process. A chemically induced acute renal failure model in the rat was used to evaluate the ability of encapsulated enzymes, along with an oral sorbent (ion exchange resin), to degrade uremic toxins in vivo. Encapsulated enzyme therapy decreased the severity of azotemia by as much as 70%. Preliminary scale up calculations indicated that oral delivery to humans would involve a practical and manageable quantity of enzymes. This is the first study using a combination of enzymes in a single delivery vehicle to degrade multiple uremic toxins.

Is thyroid frozen section too much for too little?

BACKGROUND

The role of frozen section (FS) in thyroid disease is controversial. The goal of this study was to identify a cohort of patients who may or may not benefit from FS.

METHODS

Two hundred thirty-one patients who underwent thyroidectomy were evaluated in regard to fine-needle aspiration (FNA), FS, and the extent of surgery.

RESULTS

In all, 155 patients underwent FNA, 140 patients underwent FS, and 103 patients had both. A final diagnosis of malignancy was obtained in 47 of 231 patients. FNA had a sensitivity of 50% and a specificity of 99%, and FS had a sensitivity of 50% and a specificity of 100% for diagnosing malignancy. Accounting for the clinical findings and FNA results, FS results altered the extent of thyroidectomy in 1 of 103 patients.

CONCLUSIONS

The increased costs for the operative time and the pathologists needed to obtain routine FS are not supported with any substantial benefit in patient outcome.

Bone loss following hypogonadism in men with prostate cancer treated with GnRH analogs

It is known that bone mineral density (BMD) is low in men who are hypogonadal. However, the rate and sites of bone loss following testosterone deficiency are not known. The resulting hypogonadism after GnRH analog therapy for the treatment of prostate cancer allows us to examine bone loss and bone resorption immediately after testosterone withdrawal. Therefore, we examined the effects of GnRH analog treatment on bone loss and bone resorption in men with prostate cancer. BMD and serum and urine concentrations of markers of bone turnover were determined in men with prostate cancer and in age-matched controls. Measurements were taken before GnRH therapy and 6 and 12 months after instituting therapy. After 12 months of GnRH therapy, the BMD of the total hip and ultra distal radius decreased significantly (P < 0.001) in men with prostate cancer compared with the controls. The mean bone loss was 3.3% and 5.3%, respectively. The observed reduction in BMD in the spine (2.8%) and the femoral neck (2.3%) did not reach statistical significance. No significant bone loss was observed in the control subjects. The concentration of the urine marker of bone resorption, N-telopeptide, was significantly increased from baseline and from controls at both 6 and 12 months in patients treated with GnRH analog therapy compared with control subjects (P < 0.05). The concentration of a serum marker of bone formation, bone-specific alkaline phosphatase, was not significantly different from baseline or from controls at 6 and 12 months. Thus, the decreased total hip and ultra distal radius BMD and increased urinary N-telopeptide concentration after testosterone withdrawal demonstrate an increase in trabecular bone loss and enhanced bone resorption. These findings demonstrate a significant loss of bone in men with prostate cancer after receiving GnRH therapy and suggest that the total hip and radius are the preferred sites for monitoring bone loss in older men. In addition, markers of bone resorption may be helpful.

Sequence analysis of measles virus nucleocapsid transcripts in patients with Paget's disease

It has been debated for almost 30 years whether Paget's disease of bone results from paramyxoviral infection of osteoclasts (OCs). Paramyxoviral-like nuclear inclusions are found in OCs from patients with Paget's disease, and measles virus (MV) or canine distemper virus (CDV) messenger RNA (mRNA) transcripts have been detected by in situ hybridization in bone cells from pagetic lesions. Furthermore, immunocytochemical studies have shown the presence of several paramyxoviral species in OCs from patients with Paget's disease. However, others have been unable to detect paramyxoviral transcripts in bone samples from patients with Paget's disease or marrow cultures from involved sites of patients with Paget's disease. Furthermore, no one has been able to isolate an infectious virus from pagetic bone samples or marrow cells from patients with Paget's disease, and a full-length viral gene has not been sequenced from pagetic samples. In this study, we have obtained the full-length sequence for the MV nucleocapsid (MVNP) gene in bone marrow from an involved site from a patient with Paget's disease and more than 700 base pairs (bps) of MVNP sequence in 3 other patients with Paget's disease. These sequences were undetectable in four normal marrow samples studied simultaneously. The sequences from the patients contained multiple mutations that differed from the Edmonston strain MVNP gene. These findings are consistent with the presence of a chronic MV infection in affected sites from these patients with Paget's disease.

Evaluation and treatment of postmenopausal osteoporosis

Osteoporosis is a prevalent condition among elderly women and is associated with an increased risk for fractures. With the burgeoning size of the elderly population, a practitioner is likely to face many questions regarding the evaluation and management of postmenopausal osteoporosis. This review discusses and compares available therapies. All women should have adequate calcium and vitamin D intake. Women diagnosed as having osteoporosis should be evaluated for secondary causes of osteoporosis and risk factors for falls. For women with postmenopausal osteoporosis, therapy with hormone replacement, bisphosphonates (alendronate sodium or risedronate sodium), raloxifene hydrochloride, or calcitonin should be considered. The results of ongoing studies will help refine the strategies used for management of postmenopausal osteoporosis.

Enhanced RANK ligand expression and responsivity of bone marrow cells in Paget's disease of bone

Paget's disease is characterized by highly localized areas of increased osteoclast (OCL) activity. This suggests that the microenvironment in pagetic lesions is highly osteoclastogenic, or that OCL precursors in these lesions are hyperresponsive to osteoclastogenic factors (or both). To examine these possibilities, we compared RANK ligand (RANKL) mRNA expression in a marrow stromal cell line developed from a pagetic lesion (PSV10) with that in a normal stromal cell line (Saka), and expression in marrow samples from affected bones of Paget's patients with that in normal marrow. RANKL mRNA was increased in PSV10 cells and pagetic marrow compared with Saka cells and normal marrow, and was also increased in marrow from affected bones compared with uninvolved bones from Paget's patients. Furthermore, pagetic marrow cells formed OCLs at much lower RANKL concentrations than did normal marrow. Anti-IL-6 decreased the RANKL responsivity of pagetic marrow to normal levels, whereas addition of IL-6 to normal marrow enhanced RANKL responsivity. Thus, RANKL expression and responsivity is increased in pagetic lesions, in part mediated by IL-6. These data suggest that the combination of enhanced expression of RANKL in affected bones and increased RANKL sensitivity of pagetic OCL precursors may contribute to the elevated numbers of OCLs in Paget's disease.

Dehydroepiandrosterone stimulates the estrogen response element

Studies suggest that the steroid, dehydroepiandrosterone (DHEA) can exert effects directly, in addition to its indirect role serving as a precursor for other steroids such as androgens and estrogens. Because DHEA is one of the most abundant adrenal steroids secreted in man, we investigated the functional activity of DHEA on the classic estrogen response element (ERE) in the presence of the estrogen receptor (ER) in transiently transfected cells. GT1-7 hypothalamic neuronal cells, devoid of the estrogen receptor, were transiently transfected with the estrogen receptor expression plasmid (HEGO) and the estrogen response element luciferase (ERELUC) reporter vector. As expected, a dose-response stimulation of luciferase activity was observed in cells treated with estradiol. Concentrations of estradiol from 10(-10)-10(-6) M resulted in a 136-195 percent increase in luciferase activity compared with control. A dose-response stimulation was also observed in the cells treated with DHEA. A maximum stimulation of 177 percent increase in luciferase activity compared with control was observed with DHEA at a concentration of 10(-5) M. Both the estradiol and DHEA stimulation of ERE luciferase activity was inhibited by the estrogen receptor antagonist, ICI 182,780. The aromatase inhibitor, formestane in combination with estradiol or DHEA had no effect on luciferase activity, suggesting that the effect of DHEA is independent of its conversion to estradiol. Estradiol levels, as measured by ELISA, were appropriately elevated in the estradiol-treated cells but were not significantly different from the control cells in the DHEA-treated cells. These studies suggest a functional in vitro role of DHEA in activating the ERE in the presence of the classic ER.

Phorbol ester inhibition of rat gonadotropin-releasing hormone promoter activity: role of Fos and Jun in the repression of transcription

Treatment of GT1-7 neuronal cells with the phorbol ester, 12-O-tetradecanoyl phorbol 13-acetate (TPA), inhibits GnRH gene transcription. The present studies investigated the role of AP-1 (Fos and Jun) in this repression. Treatment of cells with TPA increased c-fos mRNA 20-fold with only a 2-fold increase in c-jun mRNA levels. In transient transfection studies, a luciferase expression vector containing fragments of the 5'-flanking DNA of the rat GnRH (rGnRH) promoter was cotransfected with Fos and Jun expression vectors to mimic the effects of TPA. A dose-dependent decrease in reporter activity was noted with increasing amounts of Fos but not with Jun overexpression. Deletion analysis mapped the region that mediates repression by AP-1 to the area between -126 and -73 base pairs (bp) of the rGnRH 5'-flanking region: the same area that mediates TPA-induced repression and contains an imperfect TPA response element sequence at -99. Gel retardation assays, however, showed that a DNA fragment from -111 to -73 of the rGnRH promoter does not directly interact with Fos in GT1-7 extracts. Coexpression of Fos proteins with mutations in the DNA-binding region, the dimerization domain, or carboxy terminus partially blocked inhibition of rGnRH promoter activity. These data support a novel mechanism of AP-1 repression of GnRH transcription that is mediated by Fos interaction with other protein(s) that directly bind to the proximal rGnRH promoter.

Regulation of gonadotropin-releasing hormone (GnRH) gene expression in hypothalamic neuronal cells

1. Gonadotropin-releasing hormone (GnRH) is the hypothalamic releasing factor that controls pituitary gonadotropin subunit gene expression and indirectly gametogenesis and steroidogenesis from the gonad, which results in reproductive competence. 2. GnRH is synthesized in only about 1000 neurons in the hypothalamus and released in an episodic fashion down the median eminence to regulate gonadotropin biosynthesis. 3. Although much is known about the secretory dynamics of GnRH release, little is known about the pretranslational control of GnRH biosynthesis due to lack of appropriate model systems. The recent availability of immortalized neuronal cell lines that produce GnRH allows investigators for the first time to begin to dissect the factors that directly regulate GnRH gene expression. 4. This article reviews the current state of knowledge concerning the mechanisms that direct tissue-specific and peptide hormone control of GnRH biosynthesis.

Evidence for transcriptional inhibition of GnRH gene expression by phorbol ester at a proximal promoter region

We previously showed that activation of protein kinase C (PKC) with the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) in GT1-7 hypothalamic cells decreases GnRH mRNA levels in a dose and time dependent fashion. In the present studies, we examined the mechanism of this effect. Analysis of the half-life of GnRH mRNA levels after transcriptional arrest with actinomycin-D (5 micrograms/ml) estimated the half-life of GnRH mRNA to be 22 h. TPA treatment did not alter the GnRH mRNA half-life directly, suggesting that the effects of TPA occur predominantly at the level of gene transcription. Exposure of cells transiently transfected with various deletion constructs of the rat (r)GnRH promoter to TPA resulted in a decrease of 60% in luciferase reporter activity. This repression was maintained in constructs deleted to position -126 and was lost with further deletion to position -73. In conclusion, these experiments suggest that phorbol esters repress GnRH expression at the level of transcription through DNA sequences in the proximal rGnRH promoter.