Tereza Planck

Proteomics of Orbital Tissue in Thyroid-Associated Orbitopathy.

CONTEXT A potentially altered protein expression profile in orbital tissue from patients with thyroid-associated orbitopathy (TAO) is suspected. OBJECTIVE To detect for the first time changes in proteomic patterns of orbital connective tissue in TAO and compare these with control tissue using mass spectrometry. DESIGN Proteomics cross-sectional, comparative study. SETTING Two academic endocrine institutions. SAMPLES A total of 64 orbital and peripheral adipose tissue samples were collected from 39 patients with TAO and 25 control subjects. METHODS Samples were analyzed and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology. MAIN OUTCOME MEASURES Mean intensity values of all identified peptides per protein. RESULTS Thirty-one proteins were identified, of which 16 differentiated between controls and patients with TAO. Different protein patterns between orbital and peripheral adipose tissue were observed. Compared to controls, 10 proteins were markedly up-regulated (≥ 2-fold) in the orbital tissue of untreated patients: beta IV spectrin (6.2-fold), GTP binding G protein 2 (5.6-fold), POTE ankyrin domain family member F (5.4-fold), xylulokinase (4.1-fold), kinesin family member 1A and lipocalin 1 (both 3.6-fold), semicarbazide-sensitive metalloproteinase amine oxidase 3 and polymerase I transcript release factor (both 3.4-fold), cell-cycle protein elongin A binding protein 1 (3.3-fold), annexin A2 and cavin (both 3-fold), protein pointing to cell proliferation histone H4 (2.8-fold), and ADAM metallopeptidase with thrombospondin type 1 motif 14 (2.7-fold). The highest protein up-regulations were noted in the orbital tissue of medically untreated patients. Steroid therapy markedly reduced up-regulation of these proteins, foremost in nonsmokers. CONCLUSIONS Proteins involved in tissue inflammation, adipose tissue differentiation, lipid metabolism, and tissue remodeling were up-regulated in orbital tissue of untreated patients with TAO. Steroids decreased the expression of these proteins, whereas smoking attenuated such effect.

Vitamin D in Graves Disease: Levels, Correlation with Laboratory and Clinical Parameters, and Genetics

Objective: The aim was to compare the vitamin D levels in patients with Graves disease (GD) with the general population and to correlate the vitamin D levels with laboratory and clinical parameters in GD. Moreover, we examined the genetic variation in genes involved in the vitamin D metabolism and their association with GD. Methods: The levels of vitamin D were compared in 292 patients with newly diagnosed GD and 2,305 controls. Single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR), vitamin D binding protein (DBP), and 1-α-hydroxylase (CYP27B1) were examined for association with GD and/or Graves ophthalmopathy (GO) in 708 patients and 1,178 controls. Results: Patients with GD had significantly lower vitamin D levels compared to controls (55.0 ± 23.2 vs. 87.2 ± 27.6 nmol/L, p < 0.001). In patients with GD (n = 219), there was no association between the levels of vitamin D at diagnosis and free thyroxine (fT4), free triiodothyronine (fT3), thyrotropin receptor antibodies (TRAb), GO at diagnosis, or relapse after terminating treatment with antithyroid drugs. Two SNPs in VDR were associated with GD: rs10735810 (OR = 1.36, 95% CI: 1.02–1.36, p = 0.02) and rs1544410 (OR = 1.47, 95% CI: 1.03–1.47, p = 0.02). There was no difference in the mean vitamin D level between genotypes in either rs10735810 or rs154410. Conclusions: Patients with GD had lower vitamin D levels compared to the general population; however, the vitamin D levels did not affect the laboratory or clinical parameters of GD. SNPs in the VDR influenced the risk of GD through mechanisms other than reducing the vitamin D levels.

Study of Deiodinase Type 2 Polymorphisms in Graves’ Disease and Ophthalmopathy in a Swedish Population

Background: Deiodinase type 2 (DIO2) is an enzyme that catalyzes the production of the active form of thyroid hormone triiodothyronine (T3) from thyroxine (T4) and is important for maintaining intracellular T3 levels. Single nucleotide polymorphisms (SNPs) in DIO2 were associated with several diseases. The association of SNPs in DIO2 with Graves’ disease (GD) was suggested in 2 Russian studies. Objectives: The aim of the study was to examine whether SNPs in DIO2 are associated with GD or Graves’ ophthalmopathy (GO). Methods: Seven SNPs in the DIO2 gene – rs225014 (Thr92Ala), rs12885300, rs2267872, rs225011, rs224995, rs225015, and rs2267873 – were studied to assess their association with GD and GO. In total, 712 patients with GD with (n = 311) or without (n = 399) ophthalmopathy and 1,183 sex-matched controls from Malmö, Sweden were analyzed. In GD patients with available data, the SNPs were examined for association with the levels of free T3, free T4, thyroid-stimulating hormone receptor antibodies (TRAb), and thyroid-peroxidase antibodies (TPOAb). Results: Rs225011 was nominally associated with GD (OR 1.18, CI 1.01–1.37, p = 0.036). None of the SNPs were associated with GO. In GD patients, none of the SNPs were associated with the free-T4 (fT4), TRAb, or TPOAb levels. A weak, nonsignificant association was observed between free-T3 (fT3) levels and rs225014 and rs12885300, separately. Conclusions: Rs225011 in DIO2 was weakly associated with GD. The mechanism behind this association requires further study. None of the investigated common SNPs in DIO2 was significantly associated with GO, fT3, fT4, TRAb, or TPOAb in GD patients.

Intraorbital deiodinase type 2 expression is downregulated in chronic phase of Graves' ophthalmopathy.

metanephrines concentrations over time. If they had a similarly short half-life to catecholamines, one would expect the plasma concentrations to follow the same time course and be similarly variable between observations but this is not the case. The results from our two patients are a minor contribution to the literature and do not reliably quantify the half-lives of metanephrines. However, they are indicative and we believe consistent with other data on the pharmacokinetics of metanephrines. Definitive studies such as human pharmacokinetic studies with the administration of labelled metanephrines or careful detailed deconvolution analysis of endogenous metanephrines would provide a clearer answer. We agree that time upright and time supine are relevant to the interpretation of plasma normetanephrine. The effect of time on concentration is dependent both on the elimination half-life and ongoing production. While any period of supine rest is likely to improve diagnostic specificity, we remain concerned that 20 min may be insufficient time to adequately control for the effects of posture. For clinical purposes, we prefer to control for the effects of posture (and other confounders such as medications) in subsequent testing rather than at initial screening.