Heterogeneity of tissue IL-17 and tight junction proteins expression demonstrated in patients with autoimmune thyroid diseases

Funding Information: Funding/support: This study was supported in part by the Latvian National Research Program “BIOMEDICINE” No. 5.2.4. For the statistical analyses, the authors were assisted by the Department of Public Health and Epidemiology at Riga Stradins University. Publisher Copyright: Copyright © 2018 the Author(s). Published by Wolters Kluwer Health, Inc.Th17 cells together with their hallmark cytokine interleukin (IL)-17 were identified as crucial contributing factors in the pathogenesis of thyroid autoimmunity. The cytokine-regulated tight junction (Tj) disruption is thought to be essential in the initiation and/or development of several diseases. Still, the role of IL-17 maintaining Tj integrity in autoimmune thyroid diseases (AITDs) has not yet been evaluated. We aimed to investigate integrity of the thyroid follicle by studying immunoexpression of cellular Tj - zonula occludens (ZO)-1 and claudin-1 proteins coupled to IL-17A and CD68 detection in AITD patients compared with controls. Thirty-five adult patients undergoing thyroidectomy and presenting 18 cases of Hashimoto thyroiditis (HT), 7 of Graves' disease (GD) as well as 10 subjects of colloid goiter without autoimmune component served as controls were enrolled in this study. An immunohistochemical analysis including IL-17A, ZO-1, claudin-1, and CD68 detection was performed in each case. The correlation of IL-17A with Tj and CD68 in patients with AITD was also analyzed. Apart from inflammatory cells, we evidenced a stronger expression level of IL17A in the thyroid follicular cells in HT patients when compared with GD or colloid goiter. A significant reduction of ZO-1 immunoreactivity was observed in the thyrocytes in HT patients, whereas no significant differences were found in claudin-1 expression in HT and GD compared with colloid goiter patients. A significantly higher number of thyroid follicles with CD68-positive cells was found in HT patients than that in patients with GD or colloid goiter. In HT patients, the expression of IL-17A in the follicular cells was positively correlated with CD68 immunopositivity, whereas no association with claudin-1 or ZO-1 expression was found. GD patients did not reveal any significant correlation of IL-17A with Tj and CD68. Strong overexpression of IL-17A observed in the thyroid epithelial cells is associated with the presence of intrafollicular CD68-positive cells in HT patients. We evidenced the changes in molecules of thyrocyte junctional complexes highlighting impairment of the thyroid follicle integrity in HT, but no association with IL-17A was found.publishersversionPeer reviewe

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

Consumption of thyroid medications as an indicator of increase of thyroid morbidity in Latvia from 2011 to 2014

Funding Information: EU Horizon 2020 research and innovation programme under grant agreement No 634453; project EUthyroid. The authors thank the EUthyroid project leader Henry Völzke and the work package leader Betina H. Thuesen for designing, planning and managing the project and, in particular, morbidity data collection. Publisher Copyright: © 2019 Ieva Kalere et al., published by Sciendo 2019.The most common autoimmune disorders with clinically opposite manifestations are hypothyroidism in Hashimoto's thyroiditis and hyperthyroidism in Graves' disease. The healthcare burden of thyroid disease is substantial, resulting in substantial health care costs. The aim of the present analysis is to assess the use of thyroid medications in Latvia from 2011 to 2014 by age and gender. Our study used reimbursed medication prescriptions data, collected by the National Health Service of Latvia. The main indicator was the number of prevalent users of thyroid medications each year from 2011 to 2014, stratified by age and gender. From 2011 to 2014, the number of thyroxine users per 100 000 revealed a statistically significant increase in all age and gender groups, except in 0- to 9-year-old girls. The number of Thiamazole users among men increased in the age group from 40 to 89 years and in women age groups above 49 years. Increasing sales of both thyroid hormones and antithyroid medications are also observed in Estonia and Lithuania, indicating that growing thyroid morbidity is an issue in the whole region. The substantial increase in number of patients highlights the necessity for national guidelines on the use of thyroid function tests and standards of medical care.publishersversionPeer reviewe

Fasting-Mimicking Diet Reduces Trimethylamine N-Oxide Levels and Improves Serum Biochemical Parameters in Healthy Volunteers

Funding Information: Funding: This study was performed within the Latvian Council of Science project “Trimethylamine-N-oxide as a link between unhealthy diet and cardiometabolic risks” No. Izp-2018/1-0081, supervised by M.D.; and M.V. received funding from the European Social Fund and the state budget within the project No. 8.2.2.0/20/I/004 “Support for involving doctoral students in scientific research and studies”. Publisher Copyright: © 2022 by the authors.Elevated plasma levels of trimethylamine N-oxide (TMAO) have been proposed as a diet-derived biomarker of cardiometabolic disease risk. Caloric restriction is the most common dietary intervention used to improve cardiometabolic health; however, novel trends suggest a fasting-mimicking diet (FMD) as a more feasible alternative. FMD is a variation of intermittent fasting, based on caloric restriction and limitation of protein sources of animal origin, applied in daily cycles during a 5-day period. As TMAO is intensively produced by gut microbiota after the consumption of animal-derived products, we aim to investigate whether a 5-day FMD affects plasma TMAO levels and markers of metabolic health. To investigate whether an increase in vegetable intake possesses similar effects on TMAO levels and metabolic parameters, healthy volunteers (n = 24) were subjected to a 5-day FMD and 19 volunteers served as a reference group (VEG). This group of volunteers consumed an additional four servings of vegetables per day, but otherwise stayed on their usual diet. FMD resulted in a twofold decrease in plasma TMAO levels, which was not evident in the volunteers from the VEG group. Moreover, FMD led to a weight loss of 2.8 ± 0.2 kg and a subsequent reduction in BMI compared to baseline. The FMD group exhibited a significant elevation in plasma ketone bodies (14-fold compared to baseline) and a decrease in IGF-1 levels by 37 ± 8 ng/mL. Since fasting glucose and C-peptide levels decreased, all volunteers in the FMD group showed improved insulin sensitivity and a decreased HOMA-IR index. In contrast, in the VEG group, only a slight reduction in plasma levels of fasting glucose and triglycerides was noted. In conclusion, we show that FMD is a viable strategy to reduce plasma levels of TMAO by limiting caloric intake and animal-derived protein consumption. The reduction in the level of TMAO could be an additional benefit of FMD, leading to a reduced risk of cardiometabolic diseases.publishersversionPeer reviewe

Novel susceptibility loci identified in a genome-wide association study of type 2 diabetes complications in population of Latvia

Funding Information: The study was supported by European Regional Development Fund (ERDF) On Implementation of Activity 1.1.1.2 “Post-doctoral Research Aid” of the Specific Aid Objective 1.1.1 “To increase the research and innovative capacity of scientific institutions of Latvia and the ability to attract external financing, investing in human resources and infrastructure” of the Operational Programme “Growth and Employment”. Project No 1.1.1.2/VIAA/2/18/287 “Identification of clinical subgroups of Type 2 diabetes mellitus and application of pharmacogenetics in the development of personalized antidiabetic therapy”. The funding body was not involved in the design of the study, collection, analysis or interpretation of data, or writing the manuscript. Publisher Copyright: © 2021, The Author(s).Background: Type 2 diabetes complications cause a serious emotional and economical burden to patients and healthcare systems globally. Management of both acute and chronic complications of diabetes, which dramatically impair the quality of patients' life, is still an unsolved issue in diabetes care, suggesting a need for early identification of individuals with high risk for developing diabetes complications. Methods: We performed a genome-wide association study in 601 type 2 diabetes patients after stratifying them according to the presence or absence of four types of diabetes complications: diabetic neuropathy, diabetic nephropathy, macrovascular complications, and ophthalmic complications. Results: The analysis revealed ten novel associations showing genome-wide significance, including rs1132787 (GYPA, OR = 2.71; 95% CI = 2.02–3.64) and diabetic neuropathy, rs2477088 (PDE4DIP, OR = 2.50; 95% CI = 1.87–3.34), rs4852954 (NAT8, OR = 2.27; 95% CI = 2.71–3.01), rs6032 (F5, OR = 2.12; 95% CI = 1.63–2.77), rs6935464 (RPS6KA2, OR = 2.25; 95% CI = 6.69–3.01) and macrovascular complications, rs3095447 (CCDC146, OR = 2.18; 95% CI = 1.66–2.87) and ophthalmic complications. By applying the targeted approach of previously reported susceptibility loci we managed to replicate three associations: MAPK14 (rs3761980, rs80028505) and diabetic neuropathy, APOL1 (rs136161) and diabetic nephropathy. Conclusions: Together these results provide further evidence for the implication of genetic factors in the development of type 2 diabetes complications and highlight several potential key loci, able to modify the risk of developing these conditions. Moreover, the candidate variant approach proves a strong and consistent effect for multiple variants across different populations.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

Significantly altered peripheral blood cell DNA methylation profile as a result of immediate effect of metformin use in healthy individuals

Funding Information: The work was supported by the European Regional Development Fund under the project “Investigation of interplay between multiple determinants influencing response to metformin: search for reliable predictors for efficacy of type 2 diabetes therapy” (Project Nr.: 1.1.1.1/16/A/091). Publisher Copyright: © 2018 The Author(s).Background: Metformin is a widely prescribed antihyperglycemic agent that has been also associated with multiple therapeutic effects in various diseases, including several types of malignancies. There is growing evidence regarding the contribution of the epigenetic mechanisms in reaching metformin's therapeutic goals; however, the effect of metformin on human cells in vivo is not comprehensively studied. The aim of our study was to examine metformin-induced alterations of DNA methylation profiles in white blood cells of healthy volunteers, employing a longitudinal study design. Results: Twelve healthy metformin-naïve individuals where enrolled in the study. Genome-wide DNA methylation pattern was estimated at baseline, 10 h and 7 days after the start of metformin administration. The whole-genome DNA methylation analysis in total revealed 125 differentially methylated CpGs, of which 11 CpGs and their associated genes with the most consistent changes in the DNA methylation profile were selected: POFUT2, CAMKK1, EML3, KIAA1614, UPF1, MUC4, LOC727982, SIX3, ADAM8, SNORD12B, VPS8, and several differentially methylated regions as novel potential epigenetic targets of metformin. The main functions of the majority of top-ranked differentially methylated loci and their representative cell signaling pathways were linked to the well-known metformin therapy targets: regulatory processes of energy homeostasis, inflammatory responses, tumorigenesis, and neurodegenerative diseases. Conclusions: Here we demonstrate for the first time the immediate effect of short-term metformin administration at therapeutic doses on epigenetic regulation in human white blood cells. These findings suggest the DNA methylation process as one of the mechanisms involved in the action of metformin, thereby revealing novel targets and directions of the molecular mechanisms underlying the various beneficial effects of metformin. Trial registration: EU Clinical Trials Register, 2016-001092-74. Registered 23 March 2017, https://www.clinicaltrialsregister.eu/ctr-search/trial/2016-001092-74/LV.Peer reviewe

Stress-Related Immune Response and Selenium Status in Autoimmune Thyroid Disease Patients

Autoimmune thyroid disease (AITD), including Graves' disease (GD) or Hashimoto's thyroiditis (HT), occurs due to genetic susceptibility and environmental factors, among which the role of stressful events remains controversial. This study investigated the relationship between the number and impact of stressful life events in AITD patients with selenium status, and the Th1/Th2/Th17 immune response. The study population included three groups: HT ( n = 47), GD ( n = 13), and a control group ( n = 49). Thyroid function parameters, autoantibody levels, and the plasma levels of cytokines, selenium, selenoprotein P (SeP), and glutathione peroxidase 3 (GPx) activity were measured. Participants filled out the Life Experiences Survey. No significant differences in the number of stressful life events were found among the patients with HT, GD, and the controls. A higher (median (interquartile range)) negative stress level (8 (4-12)) than a positive stress level (3 (1-9)) was found in the HT group. The HT group showed a correlation between SeP and the positive stress level: r s = -0.296, p = 0.048, and the GD group between GPx and the negative stress level (r s = -0.702, p = 0.011). Significant positive correlations between thyroid peroxidase antibody level and the total number of major life events ( p = 0.023), the number of major life events in the last 7-12 months, and the number of major life events with no impact and a negative stress level were found. We suggest that the measurements of Th2-related cytokines and selenoproteins could be used as biomarkers for the development of AITD in cases where stress is considered a component cause of the pathogenic mechanism of the disease.publishersversionPeer reviewe

Milk as an essential source of iodine in Latvian population

Publisher Copyright: © 2017 De Gruyter Open Ltd. All rights reserved. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.Milk and dairy products are studied as alternative iodine sources, because salt iodisation is controversial due to high salt consumption leading to cardiovascular diseases. However, the iodine concentration in milk markedly varies. This study evaluated the iodine concentration in cow's milk available in the Latvian market. Iodine and fat concentration was analysed with a spectrophotometer "Varian Cary 50" based ISO 2446:2008 in 20 milk samples. Data from the Central Statistical Bureau and survey among pregnant women were used to analyse milk product consumption and its impact on iodine status. Average iodine concentration in milk samples was 457.6 (179.6) μg/L, winter samples had a higher concentration of iodine than summer samples: 563.4 (329.6) μg/L and 469.2 (162.0) μg/L, but this is not statistically significant p < 0.05. Iodine concentration in skimmed milk was 490 μg/L, milk with the reduced fat content 501.7 (174.8) μg/L, and whole milk - 422.6 (192.1)1 μg/L. Milk consumption decreased from 2002 to 2014, while yogurt and cheese consumption increased. Higher consumption of milk and milk products was related to higher urinary iodine concentration ρ = 0.115; p = 0.003. Milk and milk products are an important iodine source in Latvia and their consumption should be promoted.publishersversionPeer reviewe

Case Report : Micro-RNAs in Plasma From Bilateral Inferior Petrosal Sinus Sampling and Peripheral Blood From Corticotroph Pituitary Neuroendocrine Tumors

Funding Information: The authors acknowledge the Latvian Biomedical Research and Study Centre and the Genome Database of the Latvian Population for providing infrastructure, biological material and data. Funding Information: This research was funded by the European Regional Development Fund within the project RNA molecular determinants in development of pituitary adenoma” (1.1.1.1/18/A/089). Publisher Copyright: Copyright © 2022 Niedra, Peculis, Konrade, Balcere, Romanovs, Steina, Stukens, Sokolovska, Klovins and Rovite.Objective: Circulating miRNAs are found in bodily fluids including plasma and can serve as biomarkers for diseases. The aim of this study was to provide the first insight into the landscape of circulating miRNAs in close proximity to the adrenocorticotropic hormone (ACTH) secreting PitNET. To achieve this objective next-generation sequencing of miRNAs in plasma from bilateral inferior petrosal sinus sampling (BIPSS) - a gold standard in diagnosing ACTH-secreting PitNETs was carried out and selected miRNA candidates were further tested by RT-qPCR in independent patient cohorts. Methods: Sinistral (left) and dextral (right) BIPSS blood samples of the patient were collected in three time points: before the administration of corticotropin-releasing hormone, 5 and 15 minutes after stimulation. In differential expression analysis, sinistral plasma was compared with dextral. The selected miRNA candidates were tested in plasma by RT-qPCR in two patient groups: 1) in five ACTH secreting PitNET patients with plasma samples taken before and 24 hours after surgery, 2) in 12 ACTH secreting PitNET patients vs. 9 non-functioning PitNET patients. Results: BIPSS concluded that the highest amount of ACTH was released in the sinistral side at the 5th minute mark indicating a presence of a tumor. The highest amount of differentially expressed miRNAs was observed 5 minutes after stimulation (20 upregulated, 14 downregulated). At the 5th minute mark in sinistral plasma, two miRNAs were identified: hsa-miR-7-5p and hsa-miR-375-3p that were highly upregulated compared to other BIPSS samples and peripheral plasma samples. Further testing by qPCR revealed significant reduction of miR-7-5p in plasma 24 hours after surgery and upregulation in plasma of ACTH secreting PitNET patients compared to non-functioning PitNET patients (P =0.0013). Conclusions: By stimulating the ACTH secreting PitNET with CRH a rapid increase of two miRNAs (hsa-mir-7-5p, hsa-mir-375-3p) and ACTH can be observed in sinistral inferior petrosal (tumor side). A decrease of miR-7-5p in plasma after surgery and upregulation in plasma of ACTH secreting PitNET patients was discovered implying that further studies of this miRNA as diagnostic marker is needed.publishersversionPeer reviewe