Immunological mechanisms of autoimmune thyroid diseases : A shift in the traditional TH1/TH2 paradigm

Funding Information: This work was supported by the Latvian Council of Science project No. lzp-2018/2-0059. Publisher Copyright: © 2019 Tatjana Zaķe et al., published by Sciendo 2019.Autoimmune thyroid diseases (AITD) mainly include Hashimoto's thyroiditis (HT) and Graves' disease (GD), which are characterised by the presence of circulating antibodies against various thyroid autoantigens and infiltration of the thyroid gland by autoreactive lymphocytes. Despite the significant advancement in the knowledge of AITD pathogenesis in the last decade, the specific immunological mechanisms responsible for development of the disease are not thoroughly understood. Classically, HT has long been considered as a T helper (Th)1-mediated disease, while a Th2-driven autoimmune response is dominant for GD development. However, this classification has changed due to the description of Th17 lymphocytes, which suggested participation of these cells in AITD, particularly HT pathogenesis. Moreover, a shift in the balance between Th17 and T regulatory (Treg) cells has been observed in thyroid autoimmunity. We have observed overexpression of IL-17, the prominent effector cytokine of Th17, within thyroid tissues from HT and GD patients in our studies. The present review will focus on recent data regarding the role of Treg and Th17 lymphocytes in AITD pathogenesis. In addition, the impact and proposed mechanisms of the predominant environmental factors triggering the autoimmune response to the thyroid will be discussed.publishersversionPeer reviewe

Plasma levels of Th17-associated cytokines and selenium status in autoimmune thyroid diseases

© 2021 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.INTRODUCTION: The contribution of Th17 cytokines to autoimmune thyroid disease (AITD) is generally accepted. However, the roles of Th17 cells in the initiation and progression of Hashimoto's thyroiditis (HT) and Graves' disease (GD) remain unclear. Selenium deficiency, along with genetic predisposition and environmental factors, may have a role in thyroid autoimmunity. AIM: We aimed to assess (1) the Th17 immune response by measuring plasma levels of Th17- and Treg-associated cytokines and (2) the selenium status in treatment-naïve Latvian patients with newly diagnosed GD or HT. METHODS: Eleven GD patients, 41 HT patients, and 26 healthy subjects were recruited for this study. Plasma levels of IL-17a, IL-22, IL-23, IL-6, and IL-10 were detected by xMAP technology, while selenium was detected fluorometrically. RESULTS AND CONCLUSIONS: No significant differences in IL-17a, IL-22, IL-23, IL-6, or IL-10 levels were found among the HT patients, GD patients, and controls. In the HT patients, IL-17a levels were positively correlated with IL-22, IL-23, IL-6, and IL-10, while IL-22 was correlated with IL-6, IL-23, and IL-10. In the GD patients, IL-17a levels were positively correlated with IL-22, IL-23, and IL-10; IL-22 was positively correlated with IL-23, IL-6, and IL-10; FT3 was positively correlated with IL-17a, IL-23, and IL-10; and FT4 was positively correlated with IL-17a and IL-10 levels. Plasma selenium levels were negatively correlated with antithyroid peroxidase antibody titers in the HT patients. Although no difference in selenium levels was observed between the AITD patients and controls, the selenium status of the Latvian patients with GD or HT was at a suboptimal level.publishersversionPeer reviewe

Melatonin concentrations and sleep quality in patients with type 2 diabetes and obesity

Funding Information: The publication was supported in part by grant No. 2014.10-4/VPP-1.1.2 and -5.1.2 in the framework of the Latvian National Programme. Publisher Copyright: © 2019 Ieva Kalere et al., published by Sciendo 2019.There is a close relationship between melatonin as a circadian regulator and insulin, glucagon and somatostatin production. This study aimed to describe subgroups of type 2 diabetes mellitus (T2DM) patients that may benefit from melatonin clock-targeting properties. The study involved 38 participants: 26 T2DM patients, and 12 participants without diabetes in the control group. Subjects were asked to complete the questionnaire of Pittsburgh Sleep Quality Index (PSQI). Standard biochemical venous sample testing was performed, and a sample of saliva was collected for melatonin testing. Melatonin concentration in participants without obesity (body mass index (BMI) < 30 kg/m 2 ) was significantly higher than in obese participants: 13.2 (6.4; 23.50) pg/ml vs 5.9 (0.78; 13.1) pg/ml, p = 0.035. Subjects with BMI 30 kg/m 2 had a significantly higher PSQI score than non-obese subjects: 7 (4.5; 10) vs 5.5 (3; 7), p = 0.043. T2DM patients showed significantly lower levels of melatonin than the control group: 6.1 (0.78; 12.2) pg/ml vs 17.8 (8.2; 25.5) pg/ml, p = 0.003. T2DM patients using short-acting insulin analogues showed a significantly higher PSQI score than patients not using insulin: 9 (6; 10) vs 6 (3; 8), respectively (p = 0.025). Poor sleep quality was more prevalent in patients with diabetic retinopathy than in those without this complication (p = 0.031). Lower melatonin levels were detected in T2DM and obese patients. Furthermore, poor sleep quality was observed in T2DM patients using short-acting insulin analogues and those with diabetic retinopathy, and obese individuals.publishersversionPeer reviewe

Thyroid Autoimmunity: Exploring the Role of Th17-associated Cytokines and Pathomorphological Mechanisms Involved in the Pathogenesis of Hashimoto’s Thyroiditis and Graves’ Disease. Summary of the Doctoral Thesis

Promocijas darbs izstrādāts Rīgas Stradiņa universitātes Anatomijas un antropoloģijas institūtā un Rīgas Austrumu klīniskajā universitātes slimnīcā, Latvijā. Aizstāvēšana: Klīniskās medicīnas promocijas padomes atklātā sēdē 2021. gada 2. decembrī plkst.15.00 tiešsaistes platformā Zoom.Pēdējo dekāžu laikā ievērojami pieaugusi tādu autoimūno vairogdziedzera slimību (AIVS) kā Greivsa slimība (GS) un Hašimoto tireoidīts (HT) saslimstība un izplatība. Ir būtiski identificēt imunoloģiskos un patomorfoloģiskos faktorus, kas iesaistīti vairogdziedzera autoimunitātes izcelsmē. Lai gan 1. un 2. tipa T līdzētājšūnu (Th) izmainīta aktivitāte AIVS patoģenēzē uzskatāma par pierādītu, nesen veiktie pētījumi liecina arī par iespējamu Th17 šūnu lomu AIVS attīstībā. Turklāt Th šūnu diferenciāciju var ietekmēt selēna deficīts, veicinot šūnu un humorālās imūnatbildes disfunkciju. Šī promocijas darba mērķis bija izpētīt Th17 šūnu nozīmi HT un GS patoģenēzē, lietojot dažādas morfoloģiskās diagnostikas metodes un xMAP tehnoloģiju, kā arī korelēt iegūtos datus ar selēna statusu. Sākotnēji pētījumā tika iekļauti 29 pieauguši pacienti ar AIVS, kuriem veikta tireoīdektomija, savukārt pētījuma klīniskā daļa ietvēra 52 pacientus ar pirmreizēji diagnosticētu, iepriekš neārstētu AIVS, kā arī 26 klīniski veselas pētāmās personas, kuras iekļautas kontroles grupā. Lai izvērtētu ar Th17 saistītu imūnatbildi AIVS ietvaros, tika mērīts ar Th17 saistīto citokīnu – interleikīna (IL)-17, IL-22, IL-23, IL-6 un IL-10 – līmenis plazmā, kā arī IL-17, IL-23 un IL-1β imūnekspresijas izplatība un līmenis vairogdziedzera audos. Vairogdziedzera folikulu integritāte tika pētīta, analizējot blīvo šūnu savienojumu jeb slēgjūgļu proteīnu zonula occludens-1 un klaudīna-1 imūnekspresiju un korelējot iegūtos datus ar IL-17 un CD68 ekspresiju. Papildus tam tika noteikts selēna statuss plazmā. Starp AIVS un kontroles grupas pacientiem statistiski ticamas ar Th17 saistīto citokīnu plazmas līmeņa atšķirības netika konstatētas. Tomēr IL-17 ekspresijas līmenis tireocītos bija ievērojami augstāks pacientiem ar HT un GS nekā kontroles grupas pētāmajām personām, vienlaicīgi korelējot ar IL-23 un IL-1β imūnpozitivitāti HT grupā. Tika noteikta statistiski nozīmīga pozitīva korelācija starp ar Th17 saistīto citokīnu līmeni plazmā un hipertireozes smaguma pakāpi, kas bija neatkarīga no autoantivielu līmeņa, tādējādi norādot uz to iespējamo lomu GS patoģenēzē. HT pacientu vairogdziedzera audos tika novērotas tireocītu slēgjūgļu molekulārās pārmaiņas, uzsverot vairogdziedzera folikulu integritātes bojājumu, taču to saistība ar IL-17 netika konstatēta. Nozīmīgai vairogdziedzera enzīmu daļai, kura nodrošina gan antioksidatīvo un pretiekaisuma funkciju, gan aktivē vairogdziedzera hormonus mērķa audos, funkcionālai aktivitātei nepieciešams pietiekams daudzums selēna, tādēļ selēna deficīts tiek saistīts ar AIVS patoģenēzi un pat terapiju. Lai gan mūsu pētījumā starp AIVS pacientiem un kontroles grupu netika noteiktas statistiski nozīmīgas atšķirības plazmas selēna līmenī, rezultāti pierāda, ka selēna statuss plazmā pirmreizēji diagnosticētiem GS un HT pacientiem Latvijā ir suboptimāls. Analizējot selēna līmeni plazmā HT pacientiem, iegūta statistiska nozīmīga negatīva asociācija ar autoantivielu pret tireoperoksidāzi (TPO) titru, tādējādi liecinot par selēna imūnmodulējošo lomu AIVS patoģenēzē. Turklāt HT pacientiem ar augstāku autoantivielu pret TPO līmeni tika novērots zemāks selēna līmenis plazmā, kas liek domāt, ka selēna papildterapija šiem pacientiem var sniegt ieguvumus. Veicot šo pētījumu, tika iegūta nozīmīga informācija, kas padziļina mūsu zināšanas par vairogdziedzera autoimunitātes patoģenēzi, kā arī ar Th17 saistīto citokīnu lomu un regulatoro ietekmi, tomēr būtu nepieciešami turpmāki pētījumi, lai vēl precīzāk izpētītu Th17 šūnu lomu AIVS patoģenēzē. Pētījums apstiprina arī nepietiekamu selēna līmeni plazmā AVS pacientiem, tomēr, lai izprastu saistību starp selēna papildterapiju un imūnatbildes reakciju, nepieciešams iegūt vairāk klīnisko pētījumu datu

Vairogdziedzera autoimunitāte: ar Th17-asociēto citokīnu un patomorfoloģisko mehānismu izpēte Hašimoto tireoidīta un Greivsa slimības patoģenēzē. Promocijas darbs

The Doctoral Thesis was developed at the Institute of Anatomy and Anthropology, Rīga Stradiņš University, Latvia and Rīga East University Hospital, Latvia. Defence: at the public session of the Promotion Council of the Clinical Medicine, on 2nd December at 15.00 remotely via online platform Zoom.The prevalence and incidence of autoimmune thyroid diseases (AITD), presenting as Graves’ disease (GD) or Hashimoto’s thyroiditis (HT), has increased significantly in recent decades. It is crucial to identify immunological and pathomorphological factors involved in thyroid autoimmunity. Classically, HT has long been considered as a T helper (Th)1-mediated disease, while a Th2-driven autoimmune response is dominant for GD. Recently, Th17 cells have been established to play a role in the pathogenesis of AITD, however, their contribution to the initiation and progression of AITD remains unclear. Furthermore, selenium deficiency can impair the differentiation of Th cells, leading to dysfunction of cellular and humoral response. The aim of this thesis was to explore the role of Th17 cells in the pathogenesis of HT and GD by the use of different morphology methods and xMAP technology, and correlating these data with the selenium status. The initial study included 29 adult patients with AITD who underwent thyroidectomy, whereas subsequent clinical research project involved 52 patients with newly diagnosed, treatment-naïve AITD, as well as 26 healthy subjects served as controls. The plasma levels of Th17-associated cytokines – interleukin (IL)-17, IL-22, IL-23, IL-6, and IL-10 and the distribution and levels of immunoexpression IL-17, IL-23, and IL-1β within thyroid tissue were measured to characterize Th17 immune response in AITD. The integrity of the thyroid follicle by studying immunoexpression of cellular tight junctions – zonula occludens-1 and claudin-1 proteins, coupled to IL-17 and CD68, was explored. In addition, the selenium status was assessed. No significant differences in the plasma levels of Th17-associated cytokines were found among the patients with AITD and control subjects. However, the expression level of IL-17 in the thyrocytes was significantly higher in the HT and GD patients than in controls, simultaneously correlating with IL-23 and IL-1β immunopositivity in the HT group. Plasma Th17-associated cytokines’ levels were positively correlated with the severity of hyperthyroidism, independent of autoantibody levels, thus suggesting their possible role in GD pathogenesis. The changes in molecules of thyrocyte junctional complexes highlighting impairment of the integrity of thyroid follicle in HT were observed, but no significant association with IL-17 was found. Although no difference in selenium levels was observed between the AITD patients and controls, the results of the given research suggest the selenium status of the Latvian patients with newly diagnosed GD or HT is at a suboptimal level. Plasma selenium levels were negatively correlated with anti-thyroperoxidase (TPO) autoantibody titres in the HT patients, thus supporting the immunomodulatory role of selenium in AITD. Moreover, HT patients with higher anti-TPO autoantibody levels had lower levels of selenium, suggesting that these patients might benefit from selenium supplementation. Essential information deepening our knowledge about thyroid autoimmunity was obtained conducting this research, however, further experimental studies exploring the role and regulatory effects of Th17-related cytokines in the pathogenesis of AITD are required. More data from clinical studies are needed for a better understanding of the relationship between selenium supplementation and immune response

Combustion and Emission Characteristics of the Plant Biofuel Pellets

The paper presents the results of experimental study of composition, heating values so as combustion and emission characteristics of a new type of plant biomass pellets, produced from non-hydrolyzed residues (LHRs) of different modes of spruce wood bioethanol processing. The small pilot-scale combustion system was used for experiments. The thermal decomposition of the biofuel and ignition of volatiles was initiated using the propane flame flow as additional heat source. The combustion conditions were optimized for different rates of the primary and secondary supply to obtain cleaner and more effective heat production with reduced impact on the global warming. The results were compared with those parameters for commercial softwood pellets. It was established that for equal total mass of fuel pellets (180g), equal rates of the additional heat supply into the biomass, the pellets from non-hydrolized residues could be gasified faster with more intensive heat release than wood pellets. It was established that LHRs produced by enzymatic hydrolysis of different configurations contain more sulphur and nitrogen than LHR produced by acid hydrolysis although the emission of SO2 did not exceed the domestic requirements. At the same time NOx emission exceeded the same requirements negligibly and conventional methods for NOx emission decreasing could be used. Keywords: combustion, bio-ethanol, non-hydrolyzed residue

The Composition and Fuel Characteristics of Non-Hydrolyzed Residues from Wheat Straw Ethanol Production

The paper presents results of the experimental study of composition, heating values and combustion characteristics of granulated non-hydrolyzed residues (LHR) of separated hydrolysis and fermentation (SHF) wheat straw bioethanol processing. The LHRs ash content at 1,4 – 1,7 times exceeds the values for the native wheat straw samples. It was established that higher heating values (HHV) of the granulated LHRs (on dry mass) exceed HHV of initial wheat straw and are some lower in comparison with that of softwood granules. Granulation was carried our using the laboratory scale flat die pellet mill KAHL. The higher plasticity of LHR results in lower energy consumption during the LHR granulation in comparison with softwood sawdust (most widely used for the production of biofuel granules). Due to higher thermolability of LHR, granules on its basis are characterized with faster gasification and faster transition to the active burning stage, but the average rate of heat release and total heat output are slightly lower to that for softwood granules. LHR obtained by enzymatic hydrolysis of wheat straw show the higher nitrogen content than native wheat straw and softwood, resulting in higher NOx emissions during the LHR combustion in comparison with softwood granules. Co-firing of LHR granules with propane flame, providing 10% of the additional heat supply into the combustor allows decreasing the levels of CO emission, so promoting cleaner combustion of LHR

Multiple Products on the Basis of Rich-in-Lignin Residues from Bio-Ethanol Production – an Approach to Realization of the Bio-Refinery Concept

In the present paper the experimental studies of fuel characteristics of rich-in lignin post hydrolysis residues (LHRs) of softwood and wheat straw is described, as well as the processes of these residues granulation aimed at production of prospective fuel for domestic and industrial heating system and specific features of granules combustion are considered. The heat output at LHR wheat straw combustion reached (98%) the corresponding parameter for commercial softwood pellet, but for LHR softwood this parameter is higher by 1.2-1.4 times. The higher SO2 and NOx emissions are the feasibility of enzymatic LHRs burning. Thorough study of chemical structure and functionality, physico-chemical properties and biological activity of LHRs and products of their goal-oriented modifications together with the results of special tests clearly demonstrated the high potentials of LHRs not only as biofuel but as a raw material for novel product manufacturing