Publications by authors named "Tiina Holster"

Background: Amplicon sequencing of kingdom-specific tags such as 16S rRNA gene for bacteria and internal transcribed spacer (ITS) region for fungi are widely used for investigating microbial communities. So far most human studies have focused on bacteria while studies on host-associated fungi in health and disease have only recently started to accumulate. To enable cost-effective parallel analysis of bacterial and fungal communities in human and environmental samples, we developed a method where 16S rRNA gene and ITS1 amplicons were pooled together for a single Illumina MiSeq or HiSeq run and analysed after primer-based segregation.

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Background: Inborn errors of immunity offer important insights into mucosal immunity. In autoimmune polyendocrine syndrome type-1 (APS-1), chronic mucocutaneous candidiasis has been ascribed to neutralizing IL-17 autoantibodies. Recent evidence implicates excessive T-cell IFN-γ secretion and ensuing epithelial barrier disruption in predisposition to candidiasis, but these results remain to be replicated.

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Infertility is a global public health issue which leads many couples to seek fertility treatments, of which fertilization (IVF) is considered to be the most effective. Still, only about one-third of the women achieve live birth after the first IVF embryo transfer (IVF-ET). Factors affecting embryo implantation are poorly known, but the female reproductive tract microbiota may play a key role.

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Background/aim: Pelvic inflammatory disease (PID) is a risk factor for epithelial ovarian cancer (EOC). Chlamydia trachomatis infection, a major cause of PID, may persist in some women. Serum IgG antibodies to chlamydial TroA and HtrA are more common in ascending or repeat chlamydial infection than in uncomplicated infection.

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Background: Vaginal microbiome and the local innate immune defense, including the complement system, contribute to anti- and proinflammatory homeostasis during pregnancy and parturition. The relationship between commensal vaginal bacteria and complement activation during pregnancy and delivery is not known.

Objective: To study the association of the cervicovaginal microbiota composition to activation and regulation of the complement system during pregnancy and labor.

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Research Question: Is the composition of the endometrial or vaginal microbiota associated with recurrent pregnancy loss (RPL)?

Design: Endometrial and vaginal samples were collected from 47 women with two or more consecutive pregnancy losses and 39 healthy control women without a history of pregnancy loss, between March 2018 and December 2020 at Helsinki University Hospital, Helsinki, Finland. The compositions of the endometrial and vaginal microbiota, analysed using 16S rRNA gene amplicon sequencing, were compared between the RPL and control women, and between individual vaginal and endometrial samples. The mycobiota composition was analysed using internal transcribed spacer 1 amplicon sequencing for a descriptive summary.

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Background: Vaginal microbiota and its potential contribution to preterm birth is under intense research. However, only few studies have investigated the vaginal microbiota in later stages of pregnancy or at the onset of labour.

Methods: We used 16S rRNA gene amplicon sequencing to analyse cross-sectional vaginal swab samples from 324 Finnish women between 37-42 weeks of gestation, sampled before elective caesarean section, at the onset of spontaneous labour, and in pregnancies lasting ≥41 weeks of gestation.

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Collagen prolyl 4-hydroxylases (C-P4H-I, C-P4H-II, and C-P4H-III) catalyze formation of 4-hydroxyproline residues required to form triple-helical collagen molecules. Vertebrate C-P4Hs are α2β2 tetramers differing in their catalytic α subunits. C-P4H-I is the major isoenzyme in most cells, and inactivation of its catalytic subunit (P4ha1(-/-)) leads to embryonic lethality in mouse, whereas P4ha1(+/-) mice have no abnormalities.

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Collagen prolyl 4-hydroxylases (C-P4Hs) catalyze the formation of the 4-hydroxyproline residues that are essential for the generation of triple helical collagen molecules. The vertebrate C-P4Hs I, II, and III are [alpha(I)]2beta2, [alpha(II)]2beta2, and [alpha(III)]2beta2 tetramers with identical beta subunits. We generated mice with targeted inactivation of the P4ha1 gene encoding the catalytic alpha subunit of C-P4H I to analyze its specific functions.

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