Browsing by Subject "monozygotic twins"

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  • Kibble, Milla; Khan, Suleiman A.; Ammad-ud-din, Muhammad; Bollepalli, Sailalitha; Palviainen, Teemu; Kaprio, Jaakko; Pietiläinen, Kirsi H.; Ollikainen, Miina (2020)
    We combined clinical, cytokine, genomic, methylation and dietary data from 43 young adult monozygotic twin pairs (aged 22-36 years, 53% female), where 25 of the twin pairs were substantially weight discordant (delta body mass index > 3 kg m(-2)). These measurements were originally taken as part of the TwinFat study, a substudy of The Finnish Twin Cohort study. These five large multivariate datasets (comprising 42, 71, 1587, 1605 and 63 variables, respectively) were jointly analysed using an integrative machine learning method called group factor analysis (GFA) to offer new hypotheses into the multi-molecular-level interactions associated with the development of obesity. New potential links between cytokines and weight gain are identified, as well as associations between dietary, inflammatory and epigenetic factors. This encouraging case study aims to enthuse the research community to boldly attempt new machine learning approaches which have the potential to yield novel and unintuitive hypotheses. The source code of the GFA method is publically available as the R package GFA.
  • Koskuvi, Marja; Lehtonen, Sarka; Trontti, Kalevi; Keuters, Meike; Wu, Ying-Chieh; Koivisto, Hennariikka; Ludwig, Anastasia; Plotnikova, Lidiia; Virtanen, Pekka L. J.; Räsänen, Noora; Kaipainen, Satu; Hyötyläinen, Ida; Dhungana, Hiramani; Giniatullina, Raisa; Ojansuu, Ilkka; Vaurio, Olli; Cannon, Tyrone D.; Lönnqvist, Jouko; Therman, Sebastian; Suvisaari, Jaana; Kaprio, Jaakko; Lähteenvuo, Markku; Tohka, Jussi; Giniatullin, Rashid; Rivera, Claudio; Hovatta, Iiris; Tanila, Heikki; Tiihonen, Jari; Koistinaho, Jari (2022)
    Previous studies have implicated several brain cell types in schizophrenia (SCZ), but the genetic impact of astrocytes is unknown. Considering their high complexity in humans, astrocytes are likely key determinants of neurodevelopmental diseases, such as SCZ. Human induced pluripotent stem cell (hiPSC)-derived astrocytes differentiated from five monozygotic twin pairs discordant for SCZ and five healthy subjects were studied for alterations related to high genetic risk and clinical manifestation of SCZ in astrocyte transcriptomics, neuron-astrocyte co-cultures, and in humanized mice. We found gene expression and signaling pathway alterations related to synaptic dysfunction, inflammation, and extracellular matrix components in SCZ astrocytes, and demyelination in SCZ astrocyte transplanted mice. While Ingenuity Pathway Analysis identified SCZ disease and synaptic transmission pathway changes in SCZ astrocytes, the most consistent findings were related to collagen and cell adhesion associated pathways. Neuronal responses to glutamate and GABA differed between astrocytes from control persons, affected twins, and their unaffected co-twins and were normalized by clozapine treatment. SCZ astrocyte cell transplantation to the mouse forebrain caused gene expression changes in synaptic dysfunction and inflammation pathways of mouse brain cells and resulted in behavioral changes in cognitive and olfactory functions. Differentially expressed transcriptomes and signaling pathways related to synaptic functions, inflammation, and especially collagen and glycoprotein 6 pathways indicate abnormal extracellular matrix composition in the brain as one of the key characteristics in the etiology of SCZ.
  • Vihma, Veera; Heinonen, Sini; Naukkarinen, Jussi; Kaprio, Jaakko; Rissanen, Aila; Turpeinen, Ursula; Hämäläinen, Esa; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Mikkola, Tomi S.; Tikkanen, Matti J.; Pietiläinen, Kirsi H. (2018)
    Objective: Obesity may alter serum steroid concentrations and metabolism. We investigated this in healthy young women with increased body fat and their leaner co-twin sisters. Design: Age and genetic background both strongly influence serum steroid levels and body composition. This is a cross-sectional study of 13 female monozygotic twin pairs (age, 23-36 years), ten of which were discordant for body mass index (median difference in body weight between the co-twins, 19 kg). Methods: We determined body composition by dual energy X-ray absorptiometry and magnetic resonance imaging, serum androgens by liquid chromatography-tandem mass spectrometry, and mRNA expression of genes in subcutaneous adipose tissue and adipocytes. Results: The heavier women had lower serum dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) (P <0.05 for all) compared to their leaner co-twins with no differences in serum testosterone or androstenedione levels. Serum DHEA correlated inversely with %body fat (r = -0.905, P = 0.002), and DHT positively with SHBG (r = 0.842, P = 0.002). In adipose tissue or adipocytes, expressions of STS (steroid sulfatase) and androgen-related genes were significantly higher in the heavier compared to the leaner co-twin, and within pairs, correlated positively with adiposity but were not related to serum androgen levels. None of the serum androgen or SHBG levels correlated with indices of insulin resistance. Conclusions: Serum DHEA levels were best predicted by %body fat, and serum DHT by SHBG. These or other serum androgen concentrations did not reflect differences in androgen-related genes in adipose tissue. General or intra-abdominal adiposity were not associated with increased androgenicity in young women.
  • Sahebekhtiari, Navid; Saraswat, Mayank; Joenväärä, Sakari; Jokinen, Riikka; Lovric, Alen; Kaye, Sanna; Mardinoglu, Adil; Rissanen, Aila; Kaprio, Jaakko; Renkonen, Risto; Pietiläinen, Kirsi H. (2019)
    Purpose The purpose of this study is to elucidate the effect of excess body weight and liver fat on the plasma proteome without interference from genetic variation. Experimental Design The effect of excess body weight is assessed in young, healthy monozygotic twins from pairs discordant for body mass index (intrapair difference (Delta) in BMI > 3 kg m(-2), n = 26) with untargeted LC-MS proteomics quantification. The effect of liver fat is interrogated via subgroup analysis of the BMI-discordant twin cohort: liver fat discordant pairs (Delta liver fat > 2%, n = 12) and liver fat concordant pairs (Delta liver fat <2%, n = 14), measured by magnetic resonance spectroscopy. Results Seventy-five proteins are differentially expressed, with significant enrichment for complement and inflammatory response pathways in the heavier co-twins. The complement dysregulation is found in obesity in both the liver fat subgroups. The complement and inflammatory proteins are significantly associated with adiposity measures, insulin resistance and impaired lipids. Conclusions and Clinical Relevance The early pathophysiological mechanisms in obesity are incompletely understood. It is shown that aberrant complement regulation in plasma is present in very early stages of clinically healthy obese persons, independently of liver fat and in the absence of genetic variation that typically confounds human studies.
  • Kaye, Sanna; Lokki, A. Inkeri; Hanttu, Anna; Nissilä, Eija; Heinonen, Sini; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Saarinen, Lilli; Tynninen, Olli; Muniandy, Maheswary; Rissanen, Aila; Kaprio, Jaakko; Meri, Seppo; Pietiläinen, Kirsi H. (2017)
    Inflammation is an important mediator of obesity-related complications such as the metabolic syndrome but its causes and mechanisms are unknown. As the complement system is a key mediator of inflammation, we studied whether it is activated in acquired obesity in subcutaneous adipose tissue (AT) and isolated adipocytes. We used a special study design of genetically matched controls of lean and heavy groups, rare monozygotic twin pairs discordant for body mass index (BMI) [n = 26, within-pair difference (triangle) in body mass index, BMI >3 kg/m(2)] with as much as 18 kg mean triangle weight. Additionally, 14 BMI-concordant (BMI