Browsing by Author "Rovite, Vita"
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Item Case Report : Micro-RNAs in Plasma From Bilateral Inferior Petrosal Sinus Sampling and Peripheral Blood From Corticotroph Pituitary Neuroendocrine Tumors(2022-04-22) Niedra, Helvijs; Peculis, Raitis; Konrade, Ilze; Balcere, Inga; Romanovs, Mihails; Steina, Liva; Stukens, Janis; Sokolovska, Jelizaveta; Klovins, Janis; Rovite, Vita; Department of Internal DiseasesObjective: 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.Item Evaluation of the Possibility to Detect Circulating Tumor DNA From Pituitary Adenoma(2019-09-18) Megnis, Kaspars; Peculis, Raitis; Rovite, Vita; Laksa, Pola; Niedra, Helvijs; Balcere, Inga; Caune, Olivija; Breiksa, Austra; Nazarovs, Jurijs; Stukens, Janis; Konrade, Ilze; Pirags, Valdis; Klovins, Janis; Department of Internal DiseasesObjective: Circulating free DNA (cfDNA) in general and circulating tumor DNA (ctDNA) in particular is becoming an increasingly used form of liquid biopsy biomarkers. In this study, we are investigating the ability to detect ctDNA from the plasma of pituitary adenoma (PA) patients. Design: Tumor tissue samples were obtained from planed PA resections, before which blood plasma samples were taken. Somatic variants found in PA tissue samples were evaluated in related cfDNA, isolated from plasma samples. Methods: Sanger sequencing, as well as previously obtained whole-exome sequencing data, were used to evaluate somatic variants composition in tumor tissue samples. cfDNA was isolated from the same PA patients and competitive allele-specific TaqMan PCR and amplicon-based next-generation sequencing (NGS) approach were used for targeted detection of variants found in corresponding tumor tissue samples. Results: Using NGS-based analysis, we detected five out of 17 somatic variants in 40 to 60% of total reads, three variants in 0.50–5.00% of total read count, including GNAS c.601C>T, which was detected using ultra-deep NGS (1.78 million X) in 0.77% of amplicons reads. Nine variants were not detected. We also detected We were not able to detect variant found in PA tissue in cfDNA using cast-PCR, indicating that the portion of variant-containing ctDNA in total isolated cfDNA is too small to be detected with this method. Conclusions: For the first time, we demonstrate the possibility to detect somatic variants of PA in cfDNA isolated from patients' blood plasma. Whether the source of variant detected in cfDNA is PA should be further tested.Item Factors Affecting the Risk of Free Flap Failure in Microvascular Surgery(2016-12-01) Stepanovs, Jevgeņijs; Ozolina, Agnese; Rovite, Vita; Mamaja, Biruta; Vanags, Indulis; Department of Anaesthesiology, Intensive Care and Clinical simulationsMicrovascular free flap surgery, has become an important part of reconstructive surgery during the last decades, as it allows closure of various tissue defects and recovery of organs function. Despite surgical progress resulting in high rates of transferred tissue survival, the risk of pedicle vessels thrombosis still remains a significant problem. A total of 108 articles from Pubmed and Science Direct databases published in 2005-2015 were analysed. This review of the literature assessed the influence of patient-dependent risk factors and different perioperative management strategies on development of microvascular free flap thrombosis. Sufficient evidence for risk associated with hypercoagulation, advanced age and certain comorbidities was identified. Presently, rotational thromboelastometry allows early hypercoagulability detection, significantly changing further patient management. Identification of flap thrombosis promoting surgery-related aspects is also essential in preoperative settings. Choice of anaesthesia and postoperative analgesia, administration of different types and amounts of fluids, blood products and vasoactive agents, temperature control are no less important in perioperative anaesthesiological management. More attention should be focused on timely preoperative evaluation of patient-dependent risk factors, which can influence anaesthesiological and surgical tactics during and after microvascular free flap surgery. Perioperative anaesthesiological management strategy continues to be controversial and therefore it should be performed based on thrombotic risk assessment and patient individual needs, thus improving flap survival rates and surgical outcome.Item First Report on the Latvian SARS-CoV-2 Isolate Genetic Diversity(2021) Zrelovs, Nikita; Ustinova, Monta; Silamikelis, Ivars; Birzniece, Liga; Megnis, Kaspars; Rovite, Vita; Freimane, Lauma; Silamikele, Laila; Ansone, Laura; Pjalkovskis, Janis; Fridmanis, Davids; Vilne, Baiba; Priedite, Marta; Caica, Anastasija; Gavars, Mikus; Perminov, Dmitry; Storozenko, Jelena; Savicka, Oksana; Dimina, Elina; Dumpis, Uga; Klovins, Janis; Rīga Stradiņš UniversityRemaining a major healthcare concern with nearly 29 million confirmed cases worldwide at the time of writing, novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused more than 920 thousand deaths since its outbreak in China, December 2019. First case of a person testing positive for SARS-CoV-2 infection within the territory of the Republic of Latvia was registered on 2nd of March 2020, 9 days prior to the pandemic declaration by WHO. Since then, more than 277,000 tests were carried out confirming a total of 1,464 cases of coronavirus disease 2019 (COVID-19) in the country as of 12th of September 2020. Rapidly reacting to the spread of the infection, an ongoing sequencing campaign was started mid-March in collaboration with the local testing laboratories, with an ultimate goal in sequencing as much local viral isolates as possible, resulting in first full-length SARS-CoV-2 isolate genome sequences from the Baltics region being made publicly available in early April. With 133 viral isolates representing ~9.1% of the total COVID-19 cases during the "first coronavirus wave" in the country (early March, 2020-mid-September, 2020) being completely sequenced as of today, here, we provide a first report on the genetic diversity of Latvian SARS-CoV-2 isolates.Item Genome wide analysis of circulating miRNAs in growth hormone secreting pituitary neuroendocrine tumor patients’ plasma(2022-09-09) Niedra, Helvijs; Peculis, Raitis; Litvina, Helena Daiga; Megnis, Kaspars; Madrika, Ilona; Balcere, Inga; Romanovs, Mihails; Steina, Liva; Stukens, Janis; Breiksa, Austra; Nazarovs, Jurijs; Sokolovska, Jelizaveta; Liutkeviciene, Rasa; Vilkevicute, Alvita; Konrade, Ilze; Rovite, Vita; Department of Internal DiseasesBackground: Circulating plasma miRNAs have been increasingly studied in the field of pituitary neuroendocrine tumor (PitNET) research. Our aim was to discover circulating plasma miRNAs species associated with growth hormone (GH) secreting PitNETs versus assess how the plasma levels of discovered miRNA candidates are impacted by SSA therapy and whether there is a difference in their levels between GH secreting PitNETs versus other PitNET types and healthy individuals. Design: We compared plasma miRNA content and levels before and after surgery focusing on GH secreting PitNET patients. Selected miRNA candidates from our data and literature were then tested in a longitudinal manner in somatostatin analogues (SSA) treatment group. Additionally, we validated selected targets in an independent GH secreting PitNET group. Methods: miRNA candidates were discovered using the whole miRNA sequencing approach and differential expression analysis. Selected miRNAs were then analyzed using real-time polymerase chain reaction (qPCR). Results: Whole miRNA sequencing discovered a total of 16 differentially expressed miRNAs (DEMs) in GH secreting PitNET patients’ plasma 24 hours after surgery and 19 DEMs between GH secreting PitNET patients’ plasma and non-functioning (NF) PitNET patients’ plasma. Seven miRNAs were selected for further testing of which miR-625-5p, miR-503-5p miR-181a-2-3p and miR-130b-3p showed a significant downregulation in plasma after 1 month of SSA treatment. mir-625-5p was found to be significantly downregulated in plasma of GH secreting PitNET patients vs. NF PitNET patients. miR-625-5p alongside miR-130b-3p were also found to be downregulated in GH PitNETs compared to healthy individuals. Conclusions: Our study suggests that expression of plasma miRNAs miR-625-5p, miR-503-5p miR-181a-2-3p and miR-130b-3p in GH secreting PitNETs is affected by SSA treatment. Additionally, miR-625-5p can distinguish GH secreting PitNETs from other PitNET types and healthy controls warranting further research on these miRNAs for treatment efficacy.Item Medication for Acromegaly Reduces Expression of MUC16, MACC1 and GRHL2 in Pituitary Neuroendocrine Tumour Tissue(2021-02-15) Saksis, Rihards; Silamikelis, Ivars; Laksa, Pola; Megnis, Kaspars; Peculis, Raitis; Mandrika, Ilona; Rogoza, Olesja; Petrovska, Ramona; Balcere, Inga; Konrade, Ilze; Steina, Liva; Stukens, Janis; Breiksa, Austra; Nazarovs, Jurijs; Sokolovska, Jelizaveta; Pirags, Valdis; Klovins, Janis; Rovite, Vita; Rīga Stradiņš UniversityAcromegaly is a disease mainly caused by pituitary neuroendocrine tumor (PitNET) overproducing growth hormone. First-line medication for this condition is the use of somatostatin analogs (SSAs), that decrease tumor mass and induce antiproliferative effects on PitNET cells. Dopamine agonists (DAs) can also be used if SSA treatment is not effective. This study aimed to determine differences in transcriptome signatures induced by SSA/DA therapy in PitNET tissue. We selected tumor tissue from twelve patients with somatotropinomas, with half of the patients receiving SSA/DA treatment before surgery and the other half treatment naive. Transcriptome sequencing was then carried out to identify differentially expressed genes (DEGs) and their protein–protein interactions, using pathway analyses. We found 34 upregulated and six downregulated DEGs in patients with SSA/DA treatment. Three tumor development promoting factors MUC16, MACC1, and GRHL2, were significantly downregulated in therapy administered PitNET tissue; this finding was supported by functional studies in GH3 cells. Protein–protein interactions and pathway analyses revealed extracellular matrix involvement in the antiproliferative effects of this type of the drug treatment, with pronounced alterations in collagen regulation. Here, we have demonstrated that somatotropinomas can be distinguished based on their transcriptional profiles following SSA/DA therapy, and SSA/DA treatment does indeed cause changes in gene expression. Treatment with SSA/DA significantly downregulated several factors involved in tumorigenesis, including MUC16, MACC1, and GRHL2. Genes that were upregulated, however, did not have a direct influence on antiproliferative function in the PitNET cells. These findings suggested that SSA/DA treatment acted in a tumor suppressive manner and furthermore, collagen related interactions and pathways were enriched, implicating extracellular matrix involvement in this anti-tumor effect of drug treatment.Item Metformin strongly affects transcriptome of peripheral blood cells in healthy individuals(2019-11-01) Ustinova, Monta; Silamikelis, Ivars; Kalnina, Ineta; Ansone, Laura; Rovite, Vita; Elbere, Ilze; Radovica-Spalvina, Ilze; Fridmanis, Davids; Aladyeva, Jekaterina; Konrade, Ilze; Pirags, Valdis; Klovins, Janis; Rīga Stradiņš UniversityMetformin is a commonly used antihyperglycaemic agent for the treatment of type 2 diabetes mellitus. Nevertheless, the exact mechanisms of action, underlying the various therapeutic effects of metformin, remain elusive. The goal of this study was to evaluate the alterations in longitudinal whole-blood transcriptome profiles of healthy individuals after a one-week metformin intervention in order to identify the novel molecular targets and further prompt the discovery of predictive biomarkers of metformin response. Next generation sequencing-based transcriptome analysis revealed metformin-induced differential expression of genes involved in intestinal immune network for IgA production and cytokine-cytokine receptor interaction pathways. Significantly elevated faecal sIgA levels during administration of metformin, and its correlation with the expression of genes associated with immune response (CXCR4, HLA-DQA1, MAP3K14, TNFRSF21, CCL4, ACVR1B, PF4, EPOR, CXCL8) supports a novel hypothesis of strong association between metformin and intestinal immune system, and for the first time provide evidence for altered RNA expression as a contributing mechanism of metformin’s action. In addition to universal effects, 4 clusters of functionally related genes with a subject-specific differential expression were distinguished, including genes relevant to insulin production (HNF1B, HNF1A, HNF4A, GCK, INS, NEUROD1, PAX4, PDX1, ABCC8, KCNJ11) and cholesterol homeostasis (APOB, LDLR, PCSK9). This inter-individual variation of the metformin effect on the transcriptional regulation goes in line with well-known variability of the therapeutic response to the drug.Item Novel susceptibility loci identified in a genome-wide association study of type 2 diabetes complications in population of Latvia(2021) Ustinova, Monta; Peculis, Raitis; Rescenko, Raimonds; Rovite, Vita; Zaharenko, Linda; Elbere, Ilze; Silamikele, Laila; Konrade, Ilze; Sokolovska, Jelizaveta; Pirags, Valdis; Klovins, Janis; Faculty of MedicineBackground: 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.Item Polymorphisms in MEN1 and DRD2 genes are associated with the occurrence and characteristics of pituitary adenomas(2016-08) Peculis, Raitis; Balcere, Inga; Rovite, Vita; Megnis, Kaspars; Valtere, Andra; Stukens, Janis; Arnicane, Ligita; Nikitina-Zake, Liene; Lejnieks, Aivars; Pirags, Valdis; Klovins, JanisObjective: Although pituitary adenomas (PAs) affect a significant proportion of the population, only a fraction have the potential to become clinically relevant during an individual's lifetime, causing hormonal imbalance or complications due to mass effect. The overwhelming majority of cases are sporadic and without a clear familial history, and the genotype-phenotype correlation in PA patients is poorly understood. Our aim was to investigate the involvement of genes known for their role in familial cases on drug response and tumor suppression in the development and pathology of PAs in a patient group from Latvia. Design: The study included 143 cases and 354 controls, we investigated the role of single-nucleotide polymorphisms (SNPs) in seven genes (SSTR2, SSTR5, DRD2, MEN1, AIP, GNAS, and PRKAR1A) associated with pituitary tumor occurrence, phenotype, and clinical symptoms. Methods: Genotyping of 96 tag and nonsynonymous SNPs was performed in the genomic regions of interest. Results: We discovered a significant association (OR = 17.8, CI 0.95 = 2.18-145.5, P = 0.0002) between a rare MEN1 mutation (rs2959656) and clinically active adenoma in our patients. Additionally, rs7131056 at DRD2 was associated with a higher occurrence of extrasellar growth in patients with prolactinoma and somatotropinoma (OR = 2.79, CI 0.95 = 1.58-4.95, P = 0.0004). Conclusions: rs2959656, a nonsynonymous variant in MEN1, is associated with the development of clinically active PA. Furthermore, rs7131056 in DRD2 contributes to either faster growth of the adenoma or reduced symptomatic presentation, allowing PAs to become larger before detection.Item Replication of LZTFL1 Gene Region as a Susceptibility Locus for COVID-19 in Latvian Population(2021-10) Rescenko, Raimonds; Peculis, Raitis; Briviba, Monta; Ansone, Laura; Terentjeva, Anna; Litvina, Helena Daiga; Birzniece, Liga; Megnis, Kaspars; Kolesova, Oksana; Rozentale, Baiba; Viksna, Ludmila; Rovite, Vita; Klovins, Janis; Rīga Stradiņš UniversityItem Toll-Like Receptor 1 Locus Re-examined in a Genome-Wide Association Study Update on Anti–Helicobacter pylori IgG Titers(2022-05) Lam, Suk Yee; Mommersteeg, Michiel C.; Yu, Bingting; Broer, Linda; Spaander, Manon C.W.; Frost, Fabian; Weiss, Stefan; Völzke, Henry; Lerch, Markus M.; Schöttker, Ben; Zhang, Yan; Stocker, Hannah; Brenner, Hermann; Levy, Daniel; Hwang, Shih Jen; Wood, Alexis C.; Rich, Stephen S.; Rotter, Jerome I.; Taylor, Kent D.; Tracy, Russell P.; Kabagambe, Edmond K.; Leja, Marcis; Klovins, Janis; Peculis, Raitis; Rudzite, Dace; Nikitina-Zake, Liene; Skenders, Girts; Rovite, Vita; Uitterlinden, André; Kuipers, Ernst J.; Fuhler, Gwenny M.; Homuth, Georg; Peppelenbosch, Maikel P.; Rīga Stradiņš UniversityBackground & Aims: A genome-wide significant association between anti–Helicobacter pylori (H pylori) IgG titers and Toll-like receptor (TLR1/6/10) locus on 4p14 was demonstrated for individuals of European ancestry, but not uniformly replicated. We re-investigated this association in an updated genome-wide association study (GWAS) meta-analysis for populations with low gastric cancer incidence, address potential causes of cohort heterogeneity, and explore functional implications of genetic variation at the TLR1/6/10 locus. Methods: The dichotomous GWAS (25% individuals exhibiting highest anti–H pylori IgG titers vs remaining 75%) included discovery and replication sampls of, respectively, n = 15,685 and n = 9676, all of European ancestry. Longitudinal analysis of serologic data was performed on H pylori–eradicated subjects (n = 132) and patients under surveillance for premalignant gastric lesions (n = 107). TLR1/6/10 surface expression, TLR1 mRNA, and cytokine levels were measured in leukocyte subsets of healthy subjects (n = 26) genotyped for TLR1/6/10 variants. Results: The association of the TLR1/6/10 locus with anti–H pylori IgG titers (rs12233670; β = −0.267 ± SE 0.034; P = 4.42 × 10−15) presented with high heterogeneity and failed replication. Anti–H pylori IgG titers declined within 2–4 years after eradication treatment (P = 0.004), and decreased over time in patients with premalignant gastric lesions (P < 0.001). Variation at the TLR1/6/10 locus affected TLR1-mediated cytokine production and TLR1 surface expression on monocytes (P = 0.016) and neutrophils (P = 0.030), but not mRNA levels. Conclusions: The association between anti–H pylori IgG titers and TLR1/6/10 locus was not replicated across cohorts, possibly owing to dependency of anti–H pylori IgG titers on therapy, clearance, and antibody decay. H pylori–mediated immune cell activation is partly mediated via TLR1 signaling, which in turn is affected by genetic variation.Item Whole exome sequencing reveals novel risk genes of pituitary neuroendocrine tumors(2022-08) Peculis, Raitis; Rovite, Vita; Megnis, Kaspars; Balcere, Inga; Breiksa, Austra; Nazarovs, Jurijs; Stukens, Janis; Konrade, Ilze; Sokolovska, Jelizaveta; Pirags, Valdis; Klovins, Janis; Department of Internal DiseasesSomatic genetic alterations in pituitary neuroendocrine tumors (PitNET) tissues have been identified in several studies, but detection of overlapping somatic PitNET candidate genes is rare. We sequenced and by employing multiple data analysis methods studied the exomes of 15 PitNET patients to improve discovery of novel factors involved in PitNET development. PitNET patients were recruited to the study before PitNET removal surgery. For each patient, two samples for DNA extraction were acquired: venous blood and PitNET tissue. Exome sequencing was performed using Illumina NexSeq 500 sequencer and data analyzed using two separate workflows and variant calling algorithms: GATK and Strelka2. A combination of two data analysis pipelines discovered 144 PitNET specific somatic variants (mean = 9.6, range 0–19 per PitNET) of which all were SNVs. Also, we detected previously known GNAS PitNET mutation and identified somatic variants in 11 genes, which have contained somatic variants in previous WES and WGS studies of PitNETs. Noteworthy, this is the third study detecting somatic variants in gene RYR1 in the exomes of PitNETs. In conclusion, we have identified two novel PitNET candidate genes (AC002519.6 and AHNAK) with recurrent somatic variants in our PitNET cohort and found 13 genes overlapping from previous PitNET studies that contain somatic variants. Our study demonstrated that the use of multiple sequencing data analysis pipelines can provide more accurate identification of somatic variants in PitNETs.