Biomedical subjects
Publications and source records attributed to R S Bahn.
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Fully expressed Graves' disease involves an accumulation of glycosaminoglycan (GAG) in the retroocular connective tissue which contributes to the pathogenesis of ophthalmopathy. We treated cultured retroocular and dermal fibroblasts with recombinant interferon gamma (100 U/ml) for 16-24h and measured [3H]GAG accumulation. The cytokine stimulated [3H]GAG accumulation in retroocular fibroblast cultures obtained from eight different donors by 36-124% above control values. In contrast, interferon gamma had no consistent effect on macromolecular accumulation in dermal fibroblast cultures derived from the pretibium or from areas ordinarily uninvolved in Graves' dermopathy. These results suggest that retroocular fibroblasts may be uniquely targeted for one action of interferon gamma which involves the modulation of GAG metabolism.
We investigated the effects of several cytokines on HLA-DR expression in cultured fibroblasts derived from retroocular connective tissue and pretibial and abdominal skin of patients with Graves' ophthalmopathy (GO) and pretibial dermopathy (PTD), as well as from normal individuals. We hypothesized that differences in response to cytokines between fibroblasts from various anatomical areas might play a role in the site-selective involvement of the extrathyroidal manifestations of Graves' disease. HLA-DR expression in fibroblasts was quantitated by scanning densitometry of whole cell lysates subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Direct immunofluorescence of cell monolayers was also performed. We hypothesize that unique characteristics of these fibroblasts may play a role in GO and PTD. Cultured retroocular, pretibial, and abdominal fibroblasts from patients with Graves' disease as well as from normal individuals did not express HLA-DR spontaneously. Treatment in vitro with interferon-gamma (IFN gamma; 100 U/mL) for 5 days induced HLA-DR by 50- to 80-fold (P less than 0.0001) in fibroblasts from all sites and subjects studied. However, IFN gamma-induced HLA-DR expression was significantly greater in retroocular (P less than 0.005) and pretibial (P less than 0.0005) fibroblasts from patients with GO and PTD than in fibroblasts obtained from the same anatomical sites of normal individuals. Further, retroocular and pretibial fibroblasts from patients with GO and PTD responded to IFN gamma more vigorously than did abdominal fibroblasts from these same patients (P less than 0.0001). IFN gamma-induced HLA-DR expression was enhanced by concomitant treatment with tumor necrosis factor-alpha (100 U/mL). In contrast, treatment of retroocular fibroblasts with transforming growth factor-beta (10 ng/mL), epidermal growth factor (1 ng/mL), or interleukin-6 (IL-6; 100 U/mL) significantly attenuated IFN gamma-induced HLA-DR reactivity by 40-59% (P less than 0.05). Incubation of retroocular fibroblasts with tumor necrosis factor-alpha, IL-1 alpha (10 U/mL), IL-2 (10 U/mL), IL-6, granulocyte-macrophage colony-stimulating factor (100 U/mL), epidermal growth factor, and transforming growth factor-beta alone did not affect HLA-DR expression. These results indicate that several cytokines can influence HLA-DR expression in cultured fibroblasts. The enhanced induction of HLA-DR by IFN gamma in retroocular and pretibial fibroblasts compared with that in abdominal fibroblasts may partially explain the selective involvement of the retroocular connective tissue and pretibial skin in fully expressed Graves disease.
We hypothesize that fibroblasts obtained from the retroocular space and the pretibial skin, sites affected by the peripheral manifestations of Graves' disease, share unique characteristics that may in part explain the site specificity of Graves' ophthalmopathy (GO) and pretibial myxedema (PTM). Heat shock proteins (HSPs), synthesized by cells undergoing stress, function to maintain cellular homeostasis and are probably involved in the intracellular processing and cell surface presentation of antigens. We investigated possible differences in the expression of 70-kDa HSPs between cultured fibroblasts obtained from patients with severe GO and normal individuals. In addition, we compared HSP expression in fibroblasts derived from tissues involved in the extrathyroidal manifestation of Graves' disease (GO and PTM) with that in fibroblasts from uninvolved tissues. HSPs were detected by both immunoblotting and indirect immunofluorescence, using monoclonal antibodies that are directed against HSP72, HSP72/73 (termed HSP70), and HSP90. HSP expression at baseline and after treatment with various cytokines and heat stress was examined. At baseline, HSP72 reactivity was exclusively detected in retroocular and pretibial fibroblasts from patients with severe GO and PTM, but was not observed in abdominal fibroblasts from these patients and was not detectable in fibroblasts from any anatomical site of normal individuals. The abundance of HSP70 expression at baseline and after treatment with certain cytokines was significantly greater in retroocular and pretibial fibroblasts from patients with GO than in normal individuals. In addition, characteristic changes in the cellular localization of HSPs before and after exposure to heat stress and cytokines were observed; cell surface expression of HSP70 was detected at baseline in fibroblasts from patients, but not in normal fibroblasts. These data provide the first evidence that HSPs are differentially expressed by fibroblasts derived from tissues affected by the extrathyroidal manifestations of GD. These proteins may have a role in localized immune processes, leading to the development of GO and PTM.
Although Graves ophthalmopathy is a potentially sight threatening and disfiguring condition that can be frightening for the patient to experience, there are effective means of management. At the present time, treatment is based on the relief of excessive intraorbital pressures and is accomplished either by shrinking the orbital contents or by expanding the orbital volume. The most effective treatment modality or combination of modalities is an area of controversy. However, it must be remembered that the approach to management undertaken should be finely tuned to the needs of the particular individual afflicted with the condition. Perhaps with a greater understanding of pathophysiology, more reliable and effective treatments, based on specific pathophysiological mechanisms, may be developed. In addition, tests to reliably predict those patients most likely to progress in their disease might be developed, allowing preventive measures to be taken.
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We examined whether antibodies (present in sera from patients with Graves' disease) might be directed against a connective tissue cellular component of the anatomical regions affected in the peripheral manifestations of that disease. Accordingly, we performed immunoblot analyses of cultured retroocular and pretibial fibroblasts. Retroocular connective tissue was obtained during orbital decompression surgery (n = 7) and at autopsy from normal individuals (n = 2). Pretibial skin biopsies were obtained from patients with pretibial dermopathy (n = 3) and at autopsy (n = 2). In addition, biopsies from other regions [extraocular muscle (n = 6), thyroid (n = 2), and abdominal skin (n = 3)] were also collected at surgery or autopsy. Serum samples were obtained from patients with severe Graves' ophthalmopathy (n = 31), hyperthyroid Graves' disease without overt ophthalmopathy (n = 13), nodular thyroid disease (n = 7), Hashimoto's thyroiditis (n = 7), rheumatoid arthritis (n = 5), and systemic lupus erythematosus (n = 3) and from normal individuals (n = 33). Electrophoresed fibroblast proteins were immunoblotted with 1:100 dilutions of sera using an antihuman immunoglobulin G-alkaline phosphatase conjugate. Antibodies against a 23kDa fibroblast protein were present in the sera from 24 of 44 (56%) of patients with Graves' disease with or without ophthalmopathy, 0 of 7 nodular thyroid disease, 0 of 7 Hashimoto's thyroiditis, 0 of 5 rheumatoid arthritis, 0 of 3 systemic lupus erythematosus, and 5 of 33 (15%) normal subjects. Significant differences in the observed frequency of antibodies existed between the Graves' disease group and the normal control group (P less than 0.01) or those patients with the other conditions (P less than 0.01). This 23kDa antigen was apparent in fibroblasts derived from individuals with Graves' disease as well as normal individuals and was present in fibroblasts from all anatomical sites studied. It was the sole protein uniquely recognized by sera from patients with Graves' disease. However, this serum reactivity did not appear to be related to the presence of clinically overt ophthalmopathy or pretibial dermopathy. Subcellular localization studies disclosed that the antigen was present in the supernatant but not the pellet resulting from a 100,000 x g centrifugation of whole cell sonicates. Antibodies against a 23kDa fibroblast protein are present in the majority of sera from patients with Graves' disease and rarely in sera from either normal individuals or those with other thyroid disorders or autoimmune diseases. Our results suggest the possibility that antibodies directed against this fibroblast antigen may be related to the developm
Fibroblasts derived from retroocular connective tissue and skin were propagated in culture in an effort to identify structural and functional differences in connective tissue which might explain the apparent region-specific involvement in Graves' disease. Striking morphological differences existed between cultured cells from the two anatomical sites. Inhibition of glycosaminoglycan (GAG) accumulation by T3 and dexamethasone in these cultures was compared. Confluent cultures were labeled with [3H]acetate, and total [3H]GAG was quantitated. Fibroblasts from the skin responded to T3 (100 nmol/L) and dexamethasone (100 nmol/L) with 27% and 55% inhibition of [3H]GAG accumulation, respectively (n = 12). In contrast, retroocular fibroblasts responded with 12% and 8% inhibition (n = 6) to the two hormones. When cultures from abdominal skin and retroocular tissue were treated with n-butyrate (10 mM), a compound known to inhibit hyaluronate specifically, they responded similarly with 78% and 83% inhibition, respectively. A pulse-chase study was performed using fibroblasts from both sites, and no [3H]GAG degradation could be detected for the duration of the chase period (up to 72 h). These results suggest that retroocular fibroblasts, likely participants in the pathogenesis of Graves' ophthalmopathy, do not respond vigorously to T3 or glucocorticoids in terms of inhibition of [3H]GAG synthesis as do their dermal counterparts.
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We investigated the effect of n-butyrate (2.5 mM) on expression of the c-erb A oncogene in human colon fibroblasts. Exposure of these cells to the compound for 48 hours resulted in an increased accumulation of approximately 2.0 kb RNA which hybridized to a v-erb A cDNA probe. Hybridization to a beta-actin gene probe was unaffected by the treatment. This report is the first demonstration of a factor affecting expression of the c-erb A oncogene.
The important questions to be answered in the course of decision-making in patients with Graves' ophthalmopathy include the following: 1. Is the eye problem owing to Graves' ophthalmopathy? If not, the cause of the eye problem must be sought. 2. Does the patient have serious medical problems apart from the thyroid and the eyes? Define type and severity, and risk to life and well-being. Do they preclude anesthesia or steroid therapy? 3. Is the patient euthyroid? Define thyroid abnormality and treat. 4. Is the eye problem the highest medical priority for the patient and the physician? If not, treat the highest priority, then return to the eyes. 5. Which particular manifestations of Graves' ophthalmopathy are the most troublesome to the patient? Establish priorities according to need and rational order for surgical procedures. 6. How have the eyes been treated in the past? What has been successful? What side effects have resulted? In the evaluation of a patient with possible Graves' ophthalmopathy, no single clinical or laboratory feature is necessary or pathognomonic of the disorder. The sufficient findings for a diagnosis are a matter of clinical judgment. Several diagnostic tools including CT scanning, various ophthalmologic examinations, and studies of thyroid function are available. The physician must use these tools, along with clinical judgment, to establish the diagnosis with maximum certainty. Following this, the particular manifestations of the disease that are most troublesome to the patient must be carefully defined and assessed. Only then can the treatment be optimally tailored to the patient's needs.
Orbital connective tissue and extraocular muscles are histologically abnormal in patients with Graves' ophthalmopathy (GO). Although extraocular muscles have been extensively studied as a target for autoimmune attack in the disease, no system has been available to study retroocular fibroblasts in GO. We developed a technique to isolate fibroblasts from minced explants of connective tissue removed in the course of transantral orbital decompression surgery for GO. Postmortem specimens from individuals without evidence of thyroid disease were obtained from the same anatomical site. Confluent cells could be passaged at least 10 times with stable morphology and frozen with greater than 75% viability. An enzyme-linked immunosorbent assay was used to study the in vitro binding of serum immunoglobulin G (IgG) to these cells. We found no difference in the degree of specific binding between GO cells and cells from normal individuals. However, there was significantly greater binding of IgG from GO sera than of that from normal serum to retroocular GO fibroblasts. These results suggest that serum IgG autoantibodies against normal retroocular fibroblasts are present in some GO patients.
Treatment recommended for thyroid-associated ophthalmopathy varies with the particular expression of the disease in a given patient. Medical therapy may be beneficial in the early phase before extensive fibrosis of retro-ocular muscles and connective tissue is established. Although corticosteroids reliably suppress acute inflammatory changes, evidence supporting efficacy of plasmapheresis, immunosuppressive drugs, iodine-131 ablation, and radiotherapy is inconclusive. Surgery on eyelids, extraocular muscles, and orbit effectively rehabilitates most patients with even the most severe ophthalmopathy while having no effect on the underlying autoimmune process. Future research should include continued attempts to identify the putative target antigens in the orbit and to define the controls of glycosaminoglycan synthesis. Until prevention by immunologic or other medical means is attainable, surgery on orbit, muscles, and eyelids appears the most effective mode of treatment for correction of the functional and cosmetic consequences of the ophthalmopathy associated with autoimmune thyroid disease.
Previous work has established the presence of an unbalanced chromosome abnormality [+der(1),t(1;7)(p11;p11)] in some therapy-associated myelodysplastic disorders. Recently the EGF receptor has been found to reside at 7p11. Using a probe specific for erb B oncogene, which encodes a truncated form of the EGF receptor, we examined RNA and DNA derived from bone marrow and peripheral blood mononuclear cells from three patients with myelodysplastic syndromes (MDS) and one with acute lymphocytic leukemia (ALL), all bearing an abnormal clone in their bone marrow with a similar unbalanced 1;7 translocation. DNA-excess slot blot hybridization to 5'-32p-labeled cellular RNA revealed from ten- to thirtyfold enhancement in accumulation of mRNA specific for erb B in both peripheral blood and bone marrow cells of the three MDS patients when compared to normal controls. In addition, enhancement of H-ras mRNA accumulation was detected in some, though expression of other genes such as actin, N-ras, myc, src, B-lym, and 20 other genes was not found to be enhanced. Increased erb B expression was not apparent in mononuclear cells from patients with other hematologic disorders such as chronic lymphocytic leukemia, Hodgkin's disease, or lymphoma. Southern blot analysis of restriction-enzyme-cleaved DNA from three MDS patients with an unbalanced 1;7 translocation revealed that erb B gene was amplified at least twentyfold in peripheral blood white blood cells, while levels of actin hybridization were comparable to those of the controls. No such amplification was evident in the ALL patient. Our data suggest that +der(1),t(1;7)(p11;p11) chromosomal anomalies can be specifically associated with amplification of erb B DNA and RNA sequences.
We studied 25-year-old HLA- and blood group-identical male twins who had multiple endocrine neoplasia, type I (MEN I). At the time of initial examination, one twin (case 1) had epigastric pain and diarrhea; he was cushingoid in appearance. Further evaluation revealed primary hyperparathyroidism, Zollinger-Ellison syndrome, Cushing's disease, and hyperprolactinemia. Immunostaining of a resected pituitary specimen demonstrated both prolactin and, to a lesser extent, growth hormone reactivity. The nontumorous adenohypophysis showed corticotropic hyperplasia. In contrast, the other twin (case 2) was asymptomatic. He had only primary hyperparathyroidism and hyperprolactinemia. An invasive pituitary adenoma was resected and showed similar proportions of cells with immunoreactive prolactin and those with growth hormone; no nontumorous gland was available for study. Apparently, factors other than heredity may play a role in the expression of MEN I.
Progesterone is the major steroid synthesized by the JEG-3, BeWo, and JAR cell lines of choriocarcinoma. A lesser amount of pregnenolone is produced. The 17alpha-hydroxy derivatives of these steroids are only minimally present in three lines. The addition of fetal calf serum to the culture medium modestly increases the synthesis of these steroids, but increases the quantity of 17beta-estradiol produced by 30- to 90-fold. The addition of dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, androstenediol, and testosterone was shown to stimulate 17beta-estradiol synthesis. There is a clear dose-response relationship between the amount of testosterone added and the quantity of 17beta-estradiol produced. These results indicate that 3beta-hydroxysteroid dehydrogenase-isomerase, 17beta-ol dehydrogenase, and aromatase are active in cultured choriocarcinoma cells, whereas 17beta-hydroxylase and 17-20 desmolase do not appear to be functional in these cells. It is concluded that the stereoidogenic capabilities of choriocarcinoma cells in culture are similar to those of the in vivo placenta and support their use as an experimental model of placental steroidogenesis.
Epidermal growth factor (EGF) stimulates the production of progesterone by JEG-3, a clonal strain of human choriocarcinoma cells. Stimulation occurs in a time and dose-dependent manner. In addition, EGF increases [14C]-acetate incorporation into [14C]-cholesterol in JEG-3 cells, and this may constitute its mechanism of action in enhancing progesterone synthesis.
The appropriate management of a patient with Graves' ophthalmopathy (GO) can be determined only following a careful assessment of the signs and symptoms of the disease. A detailed examination and discussion allows the clinician to determine which components of the disease are most troublesome to that particular patient. The advantages and disadvantages of the various treatment options for each disease component can be best understood in light of current concepts of the pathogenesis of GO. This paper will begin with a discussion of the histologic and gross pathologic features of the disease, followed by a brief review of pathogenic mechanisms responsible for their development. The assessment of a patient with GO will be discussed and the modes of therapy available to address each of the signs and symptoms will be reviewed. Readers interested in a more detailed discussion of the management of GO are encouraged to read the excellent recent review by Drs. Burch and Wartofsky.