Circulating fibroblast growth factor-like substance in familial multiple endocrine neoplasia type 1

Long-Term Outcomes of Parathyroid Autografts in Primary Hyperparathyroidism

Context

Autologous implantation of parathyroid tissue is frequently utilized after parathyroidectomy in patients with heritable forms of primary hyperparathyroidism (PHPT). Data on long-term functional outcome of these grafts is sparse.

Objective

To investigate long-term outcomes of parathyroid autografts.

Methods

Retrospective study of patients with PHPT who underwent parathyroid autografts from 1991 to 2020.

Results

We identified 115 patients with PHPT who underwent 135 parathyroid autografts. Median follow-up duration since graft was 10 (4-20) years. Of the 111 grafts with known functional outcome, 54 (49%) were fully functional, 13 (12%) partially functional, and 44 (40%) nonfunctional at last follow-up. Age at time of graft, thymectomy prior to autograft, graft type (delayed vs immediate), or duration of cryopreservation did not predict functional outcome. There were 45 (83%) post-graft PHPT recurrences among 54 fully functional grafts at a median duration of 8 (4-15) years after grafting. Surgery was performed in 42/45 recurrences, but cure was attained in 18/42 (43%) only. Twelve of 18 (67%) recurrences were graft-related while remaining 6 (33%) had a neck or mediastinal source. Median time to recurrence was 16 (11-25) years in neck or mediastinal source vs 7 (2-13) years in graft-related recurrences. Median parathyroid hormone (PTH) gradient was significantly higher at 23 (20-27) in graft-related recurrence vs 1.3 (1.2-2.5) in neck or mediastinal source (P = .03).

Conclusions

Post-graft recurrence of PHPT occurs frequently within the first decade after graft and is challenging to localize. Time to recurrence after graft is significantly shorter and PTH gradient higher for graft-related recurrence. Clinical Trial Number: NCT04969926.

Genomics and Epigenomics of Pituitary Tumors: What Do Pathologists Need to Know?

Molecular pathology has advanced our understanding of many tumors and offers opportunities to identify novel therapies. In the pituitary, the field has uncovered several genetic mutations that predispose to pituitary neuroendocrine tumor (PitNET) development, including MEN1, CDKN1B, PRKRIα, AIP, GPR101, and other more rare events; however, these genes are only rarely mutated in sporadic PitNETs. Recurrent genetic events in sporadic PitNETs include GNAS mutations in a subset of somatotroph tumors and ubiquitin-specific peptidase mutations (e.g., USP8, USP48) in some corticotroph tumors; to date, neither of these has resulted in altered management, and instead, the prognosis and management of PitNETs still rely more on cell type and subtype as well as local growth that determines surgical resectability. In contrast, craniopharyngiomas have either CTNNB1 or BRAF^V600E mutations that correlate with adamantinomatous or papillary morphology, respectively; the latter offers the opportunity for targeted therapy. DICER1 mutations are found in patients with pituitary blastoma. Epigenetic changes are implicated in the pathogenesis of the more common sporadic pituitary neoplasms including the majority of PitNETs and tumors of pituicytes.

Causes of death and prognostic factors in multiple endocrine neoplasia type 1: a prospective study: comparison of 106 MEN1/Zollinger-Ellison syndrome patients with 1613 literature MEN1 patients with or without pancreatic endocrine tumors

Multiple endocrine neoplasia type 1 (MEN1) is classically characterized by the development of functional or nonfunctional hyperplasia or tumors in endocrine tissues (parathyroid, pancreas, pituitary, adrenal). Because effective treatments have been developed for the hormone excess state, which was a major cause of death in these patients in the past, coupled with the recognition that nonendocrine tumors increasingly develop late in the disease course, the natural history of the disease has changed. An understanding of the current causes of death is important to tailor treatment for these patients and to help identify prognostic factors; however, it is generally lacking.To add to our understanding, we conducted a detailed analysis of the causes of death and prognostic factors from a prospective long-term National Institutes of Health (NIH) study of 106 MEN1 patients with pancreatic endocrine tumors with Zollinger-Ellison syndrome (MEN1/ZES patients) and compared our results to those from the pooled literature data of 227 patients with MEN1 with pancreatic endocrine tumors (MEN1/PET patients) reported in case reports or small series, and to 1386 patients reported in large MEN1 literature series. In the NIH series over a mean follow-up of 24.5 years, 24 (23%) patients died (14 MEN1-related and 10 non-MEN1-related deaths). Comparing the causes of death with the results from the 227 patients in the pooled literature series, we found that no patients died of acute complications due to acid hypersecretion, and 8%-14% died of other hormone excess causes, which is similar to the results in 10 large MEN1 literature series published since 1995. In the 2 series (the NIH and pooled literature series), two-thirds of patients died from an MEN1-related cause and one-third from a non-MEN1-related cause, which agrees with the mean values reported in 10 large MEN1 series in the literature, although in the literature the causes of death varied widely. In the NIH and pooled literature series, the main causes of MEN1-related deaths were due to the malignant nature of the PETs, followed by the malignant nature of thymic carcinoid tumors. These results differ from the results of a number of the literature series, especially those reported before the 1990s. The causes of non-MEN1-related death for the 2 series, in decreasing frequency, were cardiovascular disease, other nonendocrine tumors > lung diseases, cerebrovascular diseases. The most frequent non-MEN1-related tumor deaths were colorectal, renal > lung > breast, oropharyngeal. Although both overall and disease-related survival are better than in the past (30-yr survival of NIH series: 82% overall, 88% disease-related), the mean age at death was 55 years, which is younger than expected for the general population.Detailed analysis of causes of death correlated with clinical, laboratory, and tumor characteristics of patients in the 2 series allowed identification of a number of prognostic factors. Poor prognostic factors included higher fasting gastrin levels, presence of other functional hormonal syndromes, need for >3 parathyroidectomies, presence of liver metastases or distant metastases, aggressive PET growth, large PETs, or the development of new lesions.The results of this study have helped define the causes of death of MEN1 patients at present, and have enabled us to identify a number of prognostic factors that should be helpful in tailoring treatment for these patients for both short- and long-term management, as well as in directing research efforts to better define the natural history of the disease and the most important factors determining long-term survival at present.

Molecular atherectomy for restenosis

Receptors for basic (b) and acidic (a) fibroblast growth factor (FGF) are upregulated in activated smooth muscle cells. These cells, which proliferate in response to bFGF, can thus be killed by a conjugate of bFGF and the ribosome-inactivating enzyme, saporin (which, by itself, does not enter the cells). Quiescent smooth muscle cells and other cells that have few FGF receptors are not killed. In vivo, bFGF-saporin transiently inhibits smooth muscle cell proliferation and neointimal accumulation after balloon injury to the rat carotid artery. Delivery of saporin, diagnostic imaging agents, or antisense oligodeoxynucleotides might be made even more selective by linking these substances to antibodies against the extracellular domains of the putative FGF receptor isoform specific for activated smooth muscle cells.

Anti-endothelial and anti-neuronal effects from auto-antibodies in subsets of adult diabetes having a cluster of microvascular complications

AIMS

To test autoantibodies from subsets of diabetes with painful neuropathy, maculopathy and nephropathy for effects in neurons.

METHODS

Protein-A eluates from plasma of 27 diabetic and 19 age-matched controls were tested for effects on endothelial cell survival, and neurite outgrowth in rat pheochromocytoma PC12 cells. Painful diabetic neuropathy or control autoantibodies were compared for binding to PC12-derived heparan sulfate proteoglycans. The mechanism of the effects from pathologic autoantibodies was investigated by changes in intracellular calcium in endothelial cells, whole cell current in neurons, or using the Rho kinase inhibitor Y27632.

RESULTS

Autoantibodies from diabetic patients with maculopathy, nephropathy, and painful neuropathy (n=5) caused significantly greater mean inhibition of neurite outgrowth (p<0.005) than diabetic or control patients with fewer or no complications (n=30). Painful diabetic autoantibodies (3 μg/mL) bound neuronal heparan sulfate proteoglycan (HSPG) more than autoantibodies from diabetic or control subjects without painful neuropathy (p<.0001). Inhibition of PC12 neurite outgrowth by the painful neuropathy antibodies was completely prevented by 1 μM concentrations of Y27632.

CONCLUSION

These results suggest anti-endothelial and anti-neuronal effects from auto-antibodies in a subset of diabetic patients with a cluster of microvascular complications.

Low plasma basic fibroblast growth factor is associated with laser photocoagulation treatment in adult type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen that does not normally circulate. Yet plasma bFGF-like bioactivity was increased in association with persistent microalbuminuria and retinopathy in adult type 2 diabetes mellitus. In the present study, we tested whether plasma bFGF immunoreactivity (IR) could predict the need for laser treatment of diabetic retinopathy in a baseline subset of advanced type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial (mean: age, 59 years; diabetes duration, 11 years; baseline glycosylated hemoglobin, 9.5%). Plasma bFGF-IR was determined with a sensitive and specific 2-site enzyme-linked immunoassay in 172 patients at the baseline visit. Results were dichotomized at 4.5 pg/mL, the upper limit in healthy men. There was an unexpected significant association between low baseline plasma bFGF-IR level and the interim (4 years) need for laser treatment. First laser treatment was significantly more likely to be required in patients with low compared with high baseline bFGF (19% vs 6%, P = .03 for the difference). After adjusting for clinical risk factors, low vs high bFGF (hazard ratio [HR], 5.01; P = .012), duration of diabetes (HR, 1.05; P = .050), and low-density lipoprotein cholesterol concentration (HR, 0.98; P = .027) were all significantly associated with time to first laser occurrence. These and our prior results suggest that low plasma bFGF-IR may be a marker for the presence of anti-endothelial cell autoantibodies that may contribute to the need for laser photocoagulation treatment in adult men with advanced type 2 diabetes mellitus.

Pituitary adenomas in childhood: development and diagnosis

Pituitary adenomas account for approximately 2.7% of all supratentorial tumors in the pediatric age range, and children are more likely than adults to develop a functioning adenoma. X chromosome inactivation studies indicate that pituitary adenomas arise from the clonal expression of a single mutated cell, and various intracellular mechanisms contribute to tumoral transformation. Functional pituitary tumors in childhood result in physical and biochemical effects of excess production of the oversecreted hormone, such as ACTH, prolactin, human growth hormone, TSH, LH, or FSH. In the clinical approach to pituitary adenomas, it is important to establish the presence of hormonal excess prior to undertaking imaging studies.

Differential regulation of cell growth and gene expression by FGF-2 and FGF-4 in pituitary lactotroph GH4 cells

Fibroblast growth factors, FGF-2 and FGF-4, are reported to play divergent roles in pituitary differentiation and tumor formation, stimulating cell differentiation or proliferation, respectively. However, mitogenic responses to FGFs have not been extensively characterized and little is known about the molecular mechanisms by which specific FGF isoforms may mediate distinct biological responses. Here we show that FGF-4 but not FGF-2 stimulated DNA synthesis and cell proliferation in GH4 cells. Microarray analyses revealed that FGF-4 induced expression of several oncogenes, growth factor receptors and cell cycle control proteins (e.g. cyclin D3/cdk4, N-myc, c-Raf, insulin and thyroid hormone receptors) while FGF-2 had no effect or down regulated these same genes. These transcriptional responses are consistent with a proliferative and/or tumorigenic role for FGF-4 versus a growth inhibitory effect of FGF-2. FGF-2 and FGF-4 also differentially regulated MAP kinase phosphorylation, which may underlie their isoform-specific effects on cell growth and gene expression.

Multiple endocrine neoplasia type 1 parathyroid adenoma development over time

Multiple gland parathyroid disease is one of the hallmarks of multiple endocrine neoplasia (MEN) type 1. Often mislabeled parathyroid hyperplasia, the process is actually the development of multiple adenomas. Some clinicians have reported results of selective parathyroidectomy in this group, removing only grossly enlarged glands. We argue that all the glands are at risk and should be addressed at any planned parathyroid intervention. Our hypothesis is that, given sufficient time, patients would all develop adenomas in each of the parathyroid glands. Our available data to address this issue are the parathyroidectomy results from a single institution series. Patients who had initial parathyroid exploration for hyperparathyroidism in the setting of MEN-1 were reviewed. This study includes those patients who had the weights of the resected glands documented; 23 men and 21 women met the criteria. The total weight of the parathyroid glands did not vary with the age of the patient at operation. However, the number of normal glands identified did vary significantly with age (p < 0.02), with older patients being less likely to have any normal parathyroid glands. Although total parathyroid weight may correlate with development of hypercalcemia and indications for operation, the involvement of multiple parathyroid glands in MEN-1 is a function of time, as independent events in each gland must occur. Given time, MEN-1 patients all develop multiple gland disease, and this reality must be used in planning operative management for patients with this syndrome.

Increased fibroblast growth factor-like autoantibodies in serum from a subset of patients with cancer-associated hypercalcemia

Basic fibroblast growth factor (bFGF) is a potent tumor angiogenesis factor which lacks an amino-terminal signal sequence and does not normally circulate in serum from normal subjects. Naturally-occurring autoantibodies which mimicked basic fibroblast growth factor were described in serum from patients with multiple endocrine neoplasia type 1 prolactinoma or sporadic growth-hormone-secreting adenoma associated with increased bFGF. Since bFGF was increased in serum from a variety of cancers, we used endothelial cell proliferation assay(s) to test for bioactivity in the IgG fraction of serum from 56 patients with cancer-associated hypercalcemia, and normal or control subjects. We now report increased IgG-like endothelial cell activity in serum from a hyper prolactinemic subset (4/19 breast cancer; 1/14 renal cancer; 0/23 lung cancer) of cancer-associated hypercalcemic subjects. Highest activity was found in serum from three breast cancer patients who suffered spinal cord compression/metastases. The activity had properties of antiidiotype bFGF antibodies including reaction with anti-human IgG antibodies, and complete neutralization by rabbit antibodies to intact bFGF. The activity in endothelial cells persisted after storage at 0-4 C for 5 yrs; and [prepared by SDS-PAGE and immunoblotting with anti-human IgG] had apparent mol wt corresponding to the heavy chains of IgG. Serum IgG-like activity from 5 of 5 breast cancer patients and 2 of 2 prostate cancer subjects tested [prepared by anti-bFGF antibody, protein-A immunoaffinity, and hydroxyapatite (HA) chromatography] yielded peak HA-adsorbed activity that eluted with 0.4 M sodium phosphate, and was neutralized 70% by antibodies to intact bFGF. Cancer sera mean peak specific activity (12.0 ng-eq bFGF/ug protein) (n = 7) significantly exceeded (P < 0.001) normal sera mean peak specific activity (0.46 ng-eq bFGF/ug protein) (n = 6) in the 0.4 M sodium phosphate eluate fraction from hydroxyapatite columns. These results imply that long-lasting, bioactive FGF-like autoantibodies may arise spontaneously (and contribute to pathophysiology) in subsets of cancer patients with osseous metastases.

Fibroblast growth factor activation of the rat PRL promoter is mediated by PKCdelta

Fibroblast growth factors play a critical role in cell growth, development, and differentiation and are also implicated in the formation and progression of tumors in a variety of tissues including pituitary. We have previously shown that fibroblast growth factor activation of the rat PRL promoter in GH4T2 pituitary tumor cells is mediated via MAP kinase in a Ras/Raf-1-independent manner. Herein we show using biochemical, molecular, and pharmacological approaches that PKCdelta is a critical component of the fibroblast growth factor signaling pathway. PKC inhibitors, or down-regulation of PKC, rendered the rat PRL promoter refractory to subsequent stimulation by fibroblast growth factors, implying a role for PKC in fibroblast growth factor signal transduction. FGFs caused specific translocation of PKCdelta from cytosolic to membrane fractions, consistent with enzyme activation. In contrast, other PKCs expressed in GH4T2 cells (alpha, betaI, betaII, and epsilon) did not translocate in response to fibroblast growth factors. The PKCdelta subtype-selective inhibitor, rottlerin, or expression of a dominant negative PKCdelta adenoviral construct also blocked fibroblast growth factor induction of rat PRL promoter activity, confirming a role for the novel PKCdelta isoform. PKC inhibitors selective for the conventional alpha and beta isoforms or dominant negative PKCalpha adenoviral expression constructs had no effect. Induction of the endogenous PRL gene was also blocked by adenoviral dominant negative PKCdelta expression but not by an analogous dominant negative PKCalpha construct. Finally, rottlerin significantly attenuated FGF-induced MAP kinase phosphorylation. Together, these results indicate that MAP kinase-dependent fibroblast growth factor stimulation of the rat PRL promoter in pituitary cells is mediated by PKCdelta.

Prognostic relevance of serum levels of the angiogenic peptide bFGF in advanced carcinoma of the head and neck treated by primary radiochemotherapy

BACKGROUND

The objective of this trial was to analyze the prognostic relevance of the angiogenic peptides basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and matrix metalloproteinase-2 (MMP-2) in the serum of patients with advanced carcinoma of the head and neck treated by primary radiochemotherapy.

METHODS

From 1992 to 1995, 26 patients with advanced head and neck cancer (25 stage IV, 1 stage III UICC) were treated according to the protocol of radiochemotherapy with carboplatin. The pretreatment serum levels VEGF, bFGF, and MMP-2 were measured by ELISA, and data were correlated with tumor characteristics and followed up (median time of follow up, 60 months).

RESULTS

An increase in bFGF serum level above the upper limit of normal controls showed a significant correlation with shorter time the of locoregional control (p =.036). In covariant analysis bFGF serum concentration proved to be independent of other prognostic factors like tumor site, age, total tumor volume, and response to therapy. No prognostic relevance of VEGF and MMP-2 serum levels could be determined.

CONCLUSIONS

The results of this pilot study indicate that the serum concentration of bFGF has prognostic relevance for advanced head and neck cancer.

Multiple endocrine neoplasia type 1

The recent cloning of the gene responsible for multiple endocrine neoplasia type 1 (MEN 1) has opened new avenues for both clinical and basic science research in the field of endocrine oncology. A large amount of genetic information, particularly those in relation to germline and somatic mutations, has since been published during the last 2 years. This new knowledge has provided important insights into its gene function. The significance of these advances in relation to clinical management and future directions for research is discussed.

Classification of gastric endocrine cells at the light and electron microscopical levels

This review discusses the current concepts for the classification of gastric endocrine cells subdivided according to the type of mucosa in which they are located. In the oxyntic mucosa, the most important cell type is the ECL cell, involved in the synthesis and secretion of histamine. Proteins involved in many aspects of the biology of ECL cells including the response to the gastrin stimulus, membrane transport and docking, prevention of apoptosis, calcium homeostasis, autocrine activity, and maintenance of the differentiated cell phenotype have been localized to this cell type. Other cells of the oxyntic mucosa include: the D and EC cells producing somatostatin and serotonin, respectively, delivered through long cell processes; the X (or A-like) cells, possibly producing endothelin; and the D(1) and P cells of unknown function and possibly representing morphological variants of other cell types. In the antral mucosa, the three important cell types are represented by: the gastrin-producing G cells; the somatostatin-producing D cells, which are anatomically and functionally associated with G cells; and the serotonin-producing EC cells, which are located at the bottom of antral glands.

Adult-onset angiofibroma and multiple endocrine neoplasia type I

Multiple endocrine neoplasia type 1 (MEN 1) predisposes affected persons to neoplasms of the parathyroid glands, the endocrine pancreas, the anterior pituitary, and the duodenum. We report the first case of adult-onset multiple angiofibromas of the central face associated with MEN 1. Seven siblings also developed adult-onset angiofibromas, none with evidence of tuberous sclerosis. Basic fibroblast growth factor (BFGF) is elevated in many patients with MEN 1 and may play a pathogenetic role.

Aggressive forms of gastric neuroendocrine tumors in multiple endocrine neoplasia type I

In recent classifications of gastric endocrine tumors, tumors arising in patients with multiple endocrine neoplasia type 1 (MEN-1) are regarded to be regulated by the concomitant hypergastrinemia resulting from to pancreatic or, most commonly, duodenal gastrinomas and to have a benign behavior. In this article, we report on two cases of MEN-1 gastric neuroendocrine tumors having a fatal course. Case 1 was a young male with hyperparathyroidism and Zollinger-Ellison syndrome and with florid development of multiple gastric carcinoids and multiple duodenal gastrinomas. Metastases occurred in the liver, of exclusive gastric origin, in periduodenal lymph nodes, of exclusive duodenal origin, and in perigastric lymph nodes, of mixed origin. The patient died 48 months after diagnosis. Case 2 was an adult female patient with hyperparathyroidism, adrenocortical disorders, and gastric tumors but no hypergastrinemia. The patient died 3 months after tumor diagnosis. At autopsy, the stomach showed multiple benign carcinoids and two independent neuroendocrine carcinomas not reported before in MEN-1 and massively metastatizing to lymph nodes, liver, and peritoneum. Multiple islet cell tumors mostly producing pancreatic polypeptide were found, whereas gastrinomas were seen in neither the pancreas nor the duodenum. Allelic losses at the MEN-1 gene locus in chromosome 11q13, the mechanism responsible for tumor development in MEN-1 syndrome, were demonstrated in the carcinoid tumors of case 1 and in the neuroendocrine carcinoma of case 2. We conclude that gastric neuroendocrine tumors in patients with MEN-1 may have a poor outcome, they have the same genetic mechanism as MEN-1 tumors in other organs, and they may be independent of the trophic effect of hypergastrinemia.

Pituitary cytokine and growth factor expression and action

The complex range of pituitary regulatory mechanisms reviewed here underlies the critical function of the pituitary in sustaining all higher life forms. Thus, the ultimate net secretion of pituitary hormones is determined by signal integration from all three tiers of pituitary control. It is clear from our current knowledge that the trophic hormone cells of the anterior pituitary are uniquely specialized to respond to these signals. Unravelling their diversity and complexity will shed light upon the normal function of the master gland. Understanding these control mechanisms will lead to novel diagnosis and therapy of disordered pituitary function (357).

HPE cells: a clonal endothelial cell line established from human parathyroid tissue (human parathyroid cell line)

We report the culture and cloning of human endothelial cells derived from parathyroid tissue surgically removed from a patient affected by Multiple Endocrine Neoplasia Type 1 syndrome. These cells, known as HPE, have been isolated and maintained in culture by serial passages for more than 15 months. The clonal cell line grows in a medium containing serum substitutes which favour endothelial cell growth. HPE cells replicate with a mean doubling time of 120 h, showing typical functional and morphological features of endothelial cells, such as uptake of acetylated low density lipoprotein and positive reaction for Factor VIII-Related Antigen. Basic fibroblast growth factor, vascular endothelial growth factor, insulin-like growth factor type I and ascorbic acid stimulate cell proliferation, whereas transforming growth factor beta and heparin act as inhibitory factors. Prostaglandin E2, secretin and epinephrine increased cAMP production, while human parathyroid hormone, histamine and glucagon were inert. Cells were found to express pro-collagen alpha 1 (type I) mRNA. In HPE cells Restriction Fragments Length Polymorphism and PCR analysis did not show allelic loss at chromosome 11q12-13, known to be a typical feature of MEN 1 parathyroid tumors. These cells are the first example of an established normal human clonal cell line with an endothelial phenotype.

Heparin-binding secretory transforming gene (hst) facilitates rat lactotrope cell tumorigenesis and induces prolactin gene transcription

We have shown previously that human prolactinomas express transforming sequences of the heparin-binding secretory transforming gene (hst) which encodes fibroblast growth factor-4 (FGF-4). To elucidate the role of hst in pituitary tumorigenesis we treated primary rat pituitary and pituitary tumor cell cultures with recombinant FGF-4 and also stably transfected pituitary cell lines with full-length human hst cDNA. Transfectants were screened for hst mRNA expression and FGF-4 production. FGF-4 (0.1-50 ng/ml) caused a dose-dependent 2.5-fold increase of prolactin (PRL) secretion (P < 0.001) in GH4 cells and up to 60% (P < 0.05) in primary cultures, while decreasing growth hormone release (P < 0.001). GH4 hst transfectants displayed markedly enhanced basal PRL secretion (threefold, P < 0.001) and also proliferated faster (P < 0.001). FGF-4 treatment of wild-type GH4 cells, transiently transfected with an expression construct (rPRL.luc) containing a luciferase reporter driven by the rPRL promoter, resulted in a dose-dependent increase of up to 3.3-fold in PRL transcriptional activity. Tumors derived from in vivo subcutaneous injection of GH4 hst-transfected cells strongly expressing FGF-4 grew more aggressively as assessed by histologic invasiveness and proliferating cell nuclear antigen staining (P < 0.01). The results indicate that hst overexpression mediates lactotrope tumor growth and potently stimulates PRL synthesis. Thus, hst may directly facilitate prolactinoma development via paracrine or autocrine action of its secreted protein, FGF-4.

Stimulation of endothelial cells by doses of basic FGF-saporin that are lethal to smooth muscle cells

Basic fibroblast growth factor (FGF) receptors are up-regulated in proliferating (vs. quiescent) aortic smooth muscle cells, according to the results of recent studies. This up-regulation allows the ribosome inactivator saporin (if linked to basic FGF) to enter and kill proliferating, but not quiescent smooth muscle cells in vitro and in vivo. The authors now report that endothelial cells exhibit a different response. In 10% serum, FGF-SAP (0.1-1 nM) stimulates protein synthesis and cell division in subconfluent endothelial cells, but inhibits protein synthesis and cell division in subconfluent smooth muscle cells. Endothelial cells were inhibited at 10 nM FGF-SAP. A stimulatory response was seen in smooth muscle cells only at 0.1 nM FGF-SAP, and only after serum deprivation. Both cell types were resistant to FGF-SAP at high cell density. These responses correlated with FGF receptor density, which was sixfold higher in smooth muscle than endothelial cells and twice as high in serum-free smooth muscle cells as in serum-deprived smooth muscle cells. Moreover, a dose of FGFSAP that inhibited neointimal smooth muscle accumulation after balloon injury did not inhibit reendothelialization. Thus, there is a dose range at which FGF-SAP has unique properties that may make it useful in the treatment of vascular injury.

Adrenal lesion in multiple endocrine neoplasia type 1

BACKGROUND

Multiple endocrine neoplasia (MEN) type 1 is accompanied by adrenal involvement, but characteristics and clinical handling of this lesion have been insufficiently explored.

METHODS

Patients with MEN 1 (n = 43) were monitored (mean, 6.3 years) with annual biochemical and radiologic adrenal evaluation. Adrenal specimens were examined by in situ RNA-RNA hybridization for expression of the MEN1 candidate gene phospholipase C beta 3 (PLC beta 3) and immunostaining for insulin-like growth factor-1 receptor.

RESULTS

Altogether 17 patients (40%) displayed adrenal enlargement, which was limited to the adrenal cortex and showed signs of progression, marked atypia, and cancer development in three of them. Only the carcinoma exhibited adrenocortical hormone excess. PLC beta 3 was expressed in the hyperplastic and adenomatous proliferation but not the carcinoma. Pancreatic endocrine tumors with insulin-proinsulin excess were overrepresented in the patients with adrenocortical involvement, but significant insulin-like growth factor-1 receptor immunoreactivity was restricted to the carcinoma.

CONCLUSIONS

The prevalent adrenocortical lesion associated with MEN 1 requires regular attention because of malignant potential. It was unrelated to loss of constitution heterozygosity for the MEN1 locus (11q13) and PLC beta 3 expression, except for the cortical carcinoma exhibiting allelic losses involving also the Wiedemann-Beckwith gene at 11p15. Mechanisms for mitogenic relationships between the pancreatic and adrenal lesions of MEN 1 demand further clarification.

Serum evaluation of basic fibroblast growth factor in cervical cancer patients

We present the data of 105 serum samples from 20 patients suffering from cervical cancer. Mean serum levels of basic fibroblast growth factor (bFGF) in patients with or without tumor present were 31.3 +/- 32.1 (minimum 0, maximum 156.7) pg/ml and 4.8 +/- 6.8 (minimum 0, maximum 29.6) pg/ml, respectively (P = 0.0001). bFGF reached a sensitivity of 65.7% at a specificity of 91.5% when applying a cut-off level of 15 pg/ml. Four patients relapsed after complete remission. A continuous increase of bFGF serum levels before the clinical detection of relapse (lead time) was seen in two cases with a mean lead time of 4 months. Preoperative serum levels were not of prognostic value and showed no correlation with pelvic lymph node metastasis. These preliminary results indicate that in cervical cancer patients soluble bFGF may be useful in early detection of primary tumors, recurrences and monitoring of therapy.

Expression of basic fibroblast growth factor in hyperplastic parathyroid glands from patients with multiple endocrine neoplasia type I

Primary hyperparathyroidism was investigated using the presence of basic fibroblast growth factor (bFGF) from the immunohistochemical viewpoint with an anti-bFGF antibody in hyperplastic parathyroid glands of patients with multiple endocrine neoplasia type I (MEN-I) and of patients with non-MEN. The results corresponded well with the data from the DNA analysis. Twenty-five hyperplastic parathyroid glands from 11 patients with MEN-I and 38 glands from 20 patients with non-MEN primary hyperparathyroidism were stained immunohistochemically according to the avidin-biotin-peroxidase complex procedure. When 50% or more of the cells appeared uniformly stained, it was judged positively stained. In addition, 18 hyperplastic parathyroid glands from patients with MEN-I patients and 24 hyperplastic parathyroid glands from non-MEN patients were also analyzed for DNA using flow cytometry. The ratio of positively stained hyperplastic parathyroid glands was 72% in MEN-I patients and 18% in non-MEN patients. The difference between the two groups was significant (p < 0.01). The nodules consisted of oxyphilic cells in 7 of 25 hyperplastic parathyroid glands from MEN-I patients and in 10 of 38 hyperplastic parathyroid glands from non-MEN patients, and all the cells were positive for bFGF. There was no significant correlation between bFGF staining and the DNA ploidy pattern. bFGF possibly plays a role in the development of parathyroid gland hyperplasia, especially in MEN-I patients. The increase of oxyphilic cells may be correlated with the expression of bFGF.

Identification of soluble forms of the fibroblast growth factor receptor in blood

We have purified three acidic (FGF-1) and basic (FGF-2) fibroblast growth factor binding proteins (FGF-BP1, FGF-BP2, and FGF-BP3) from human plasma and calf serum and demonstrate the presence of these circulating FGF-BPs in blood. Each are truncated forms of the high-affinity FGF receptor (FGFR-1). FGF-BP1 and FGF-BP2 have estimated molecular masses of 70-85 kDa and 55-60 kDa, respectively, and are detected by using 125I-labeled FGF-2 ligand blotting. Immunoblotting with four distinct antibodies to FGFR-1 reveals that FGF-BP1 and FGF-BP2 are immunologically and biochemically related to the extracellular domain of FGFR-1. Reverse-phase HPLC chromatography resolves FGF-BP2 into two proteins with estimated molecular masses of 55 kDa and 60 kDa. Protein sequencing of the amino terminus of FGF-BP2 and FGF-BP3 reveals identity with the extracellular domain of the two-IgG-loop form of human FGFR-1. The FGF-BPs do not require heparin to bind FGF-2 on affinity columns, but heparin does enhance their recovery from blood. These FGF-BPs may play an important physiological role in regulating the biological activity of FGF and the other members of the FGF family of growth factors.

Production of basic fibroblast growth factor by gastric carcinoid tumors and their putative cells of origin

Using immunohistochemical techniques a subpopulation of endocrine cells in the human oxyntic mucosa was found to react with antibodies against basic fibroblast growth factor (bFGF). These cells were identified as histamine-producing enterochromaffin-like (ECL) cells and, to a minor extent, serotonin-producing enterochromaffin cells. Basic fibroblast growth factor immunoreactive cells were most frequently found in hyperplastic lesions of ECL cells occurring in hypergastrinemic patients (20 of 27 cases) and in ECL cell carcinoid tumors (10 of 17 cases). In addition, bFGF mRNA was demonstrated by Northern blot analysis of homogenates from two gastric carcinoids cytologically characterized as pure ECL cell tumors. Although the function of bFGF in normal cells remains unknown, its production in neoplastic conditions may be responsible for the associated desmoplastic and angioblastic proliferations. Moreover, secretion of bFGF by hyperplastic or neoplastic ECL cells may contribute to the circulating levels of the bFGF-like mitogenic factor identified in patients affected by multiple endocrine neoplasia type 1 syndrome.

Hematopoietic endocrinology: role of autoantibodies to soluble mediators in hematopoiesis

The development and maturation of blood cells in known to be regulated by soluble factors. We propose that immunologic alterations, specifically autoantibodies, to these soluble factors may affect hematopoiesis.

Heterogeneous size of the parathyroid glands in familial multiple endocrine neoplasia type 1

OBJECTIVE

We wished to determine whether there was size heterogeneity of the parathyroid glands in patients with familial multiple endocrine neoplasia type 1 (FMEN1) and primary hyperparathyroidism.

DESIGN

At the National Institutes of Health we performed a retrospective analysis of parathyroid gland volume either from initial or repeat parathyroid exploration.

PATIENTS

We studied subjects with FMEN1 and primary hyperparathyroidism.

MEASUREMENTS

The parathyroid gland volume was estimated from recorded orthogonal diameters. Volume could also be estimated conservatively in many glands for which one or more diameters were not recorded. Reproducibility of volume measurements was tested with a series of clay gland models. Indices of variability (among glands at an operation or among replicate measurements of a clay model) were the ratio of maximum volume/minimum volume and the average standard deviation of the log volume.

RESULTS

The most complete data were from eight initial operations with three dimensions recorded for all four glands. Volume heterogeneity was indicated by the average ratio of 9.6 for the maximum/minimum gland volume within an operation. The size heterogeneity was even greater among other subgroups. For example, the average ratio of maximum/minimum gland volume within an operation was 17 among five initial operations with four glands removed, but lacking measurements of three dimensions for some glands. Little of this size heterogeneity could be attributed to measurement error since eight replicate measurements on a model gland yielded a maximum/minimum volume ratio of 1.45.

CONCLUSIONS

There is a wide heterogeneity in size of the parathyroid glands in the patients with FMEN1 and primary hyperparathyroidism.

Growth factors and the anterior pituitary

Normal growth and secretion in the pituitary gland are dependent upon the co-ordinated action of a large number of extracellular growth factors, neuropeptides and peripheral hormones acting on their respective cellular receptors and via complex intracellular signalling pathways. The pituitary and hypothalamus are exposed to a large number of growth factors, several of which have well-documented effects on secretory function and may act as physiological modulators of pituitary hormone synthesis and release. IGF-I, for example, almost certainly acts as a feedback regulator of GH secretion. Despite well-documented mitogenic effects in other tissues, little is known about the role of these growth factors in normal pituitary cell turnover, compensatory hyperplasia or adenoma formation. There is now good evidence, however, that at least some of the hypothalamic releasing peptides are mitogenic for their respective pituitary cell subpopulations. The aetiology of pituitary tumours remains poorly understood but some appear to develop as a result of somatic mutation. Such mutations could enhance growth by causing altered expression of growth factors or their receptors, or constitutive activation of proteins involved in the intracellular mitogenic signal. Abnormalities have been documented at each of these levels in human pituitary tumours. The identification of an activating point mutation in the alpha subunit of Gs, the stimulatory regulatory peptide of adenylyl cyclase, in a proportion of somatotroph adenomas represents a major advance in our understanding of pituitary tumour pathogenesis. This and other findings may ultimately lead to new therapeutic approaches to the management of pituitary disease.

Etiologies of parathyroid gland dysfunction in primary hyperparathyroidism

Primary hyperparathyroidism is caused by defects in the parathyroid gland. Investigations have implicated three interesting genes whose mutation can cause primary hyperparathyroidism. Familial hypocalciuric hypercalcemia is believed to be an atypical form of primary hyperparathyroidism with an inherited defect in calcium recognition expressed not only in all parathyroid chief cells (thus a polyclonal defect) but in some renal tubular cells as well. In typical primary hyperparathyroidism a monoclonal parathyroid tumor is usually the central cause. Either of two apparently different genes on the long arm of chromosome 11 has been implicated in development of a parathyroid tumor clone. One gene (D11S287) was shown to have undergone a rearrangement with the parathyroid hormone gene on the short arm of the same chromosome (pericentromeric inversion) in a small fraction of tumors; the D11S287 locus may encode a growth stimulator. Another gene, the locus for familial multiple endocrine neoplasia type 1 (FEMEN1), is likely to encode a growth inhibitor. Inactivation of this gene or another nearby gene by somatic mutation has been indirectly implicated in one-quarter of sporadic parathyroid adenomas and in more than half of parathyroid tumors in FMEN1. In conclusion, studies have suggested three different mechanisms for parathyroid gland dysfunction in primary hyperparathyroidism: (1) a defect in calcium recognition, (2) a monoclonal tumor from overexpression of a growth stimulator, or (3) a monoclonal tumor from inactivation of a growth inhibitor.

Sipple syndrome with lichen amyloidosis as a paracrinopathy: pleiotropy, heterogeneity, or a contiguous gene?

A five-generation white family with multiple endocrine neoplasia type 2A had six affected members. Two, a mother and her daughter, had interscapular cutaneous pruritic lesions resembling macular/lichen amyloidosis. In the daughter, light microscopy showed homogeneous aggregates in the papillary dermis. Crystal violet staining showed metachromasia and indicated that the deposits were amyloid. This is the fourth family with familial medullary thyroid carcinoma with cutaneous amyloidosis and as such it allowed comparative analysis. Genetic heterogeneity, a contiguous gene, and pleiotropy were considered. It appears that multiple endocrine neoplasia type 2A/familial medullary thyroid carcinoma with cutaneous amyloidosis represents the phenotypic variability of the expression of a pleiotropic gene. The condition is one of the predominantly ectodermal autosomal dominant phakomatoses and is most likely a paracrinopathy.

Multiple forms of bFGF: differential nuclear and cell surface localization

The single copy gene for human basic fibroblast growth factor (bFGF) has been shown to encode not one but multiple proteins of 24, 23, 22 and 18 kD. Although bioactivities of the 18 kD protein are currently used to define bFGF gene function, it is not yet known if the three larger proteins have these same bioactivities or whether they will serve to define new bFGF gene functions. In this report we present a comparative study describing the de novo synthesis, transport, processing and intracellular location of individual bFGF isoforms. Data from cDNA mutagenesis and COS cell expression experiments show that individual isoforms are differentially localized to either the cell surface or to the nucleus. The 24, 23 and 22 kD proteins (CUG-mediated initiation) exclusively localize in the nucleus while the 18 kD protein (AUG-mediated initiation) is preferentially exported onto the cell surface, but is not released into the surrounding culture medium. Specific CUG or AUG translation initiation codons are necessary and sufficient for the synthesis of each isoform examined and thereby, indirectly, mediate differential localization. Since bFGF does not contain the characteristic signals predicted for cell surface or nuclear targeting, our continuing studies will either unmask its functionally equivalent domain(s) or will identify the requisite participation of yet unknown cellular components.