Studies on the pathogenesis and laboratory diagnosis of Lyme borreliosis

Lyme borreliosis, the most common tick-borne disease in the northern hemisphere, is caused by Borrelia burgdorferi sensu lato spirochetes (later Borrelia). They can infect humans through bites of infected Ixodes ticks. If the infection is not treated at the early local stage of the disease, spirochetes can disseminate via the blood vasculature into distant tissues of the human body and cause symptoms in the joints, the heart, and the nervous system. Infection of the central nervous system is called Lyme neuroborreliosis. Lyme neuroborreliosis is diagnosed based on neurological symptoms, pleocytosis, and intrathecal production of Borrelia-specific antibodies. Recently, chemokine CXCL13 has been introduced as a new biomarker for diagnostics of Lyme neuroborreliosis. The first aim of this study was to characterize the dissemination of Borrelia by in vitro adhesion studies conducted under shear stress and by imaging the infection in vivo in mice. The second aim was to evaluate the use of cytokines as biomarkers for Lyme neuroborreliosis. The studies revealed that decorin binding proteins of Borrelia act in a flow-tolerant manner mediating adherence into vascular endothelium under the mechanical force caused by the liquid flow. In addition to decorin, decorin binding proteins were shown to bind biglycan, a proteoglycan which is expressed on endothelium more abundantly than decorin. Moreover, dissemination of Borrelia can be imaged in vivo in mice using positron-emission tomography. The studies also showed that CXCL13 is the most specific cytokine biomarker for Lyme neuroborreliosis and the concentration of CXCL13 can reliably be measured of Lyme neuroborreliosis patients’ cerebrospinal fluid samples with a point-of-care test. Overall, the studies gave new information on the pathogenesis of Lyme borreliosis and helped to improve the disease diagnostics.Tutkimuksia Lymen borrelioosin patogeneesistä ja diagnostiikasta Pohjoisen pallonpuoliskon yleisimmän puutiaisvälitteisen infektion, Lymen borrelioosin, aiheuttajia ovat Borrelia burgdorferi sensu lato ryhmän spirokeettabakteerit (myöhemmin Borrelia). Ne voivat levitä ihmiseen infektoituneiden Ixodes-puutiaisten välityksellä. Jos tautia ei hoideta heti infektion aikaisessa paikallisessa vaiheessa, spirokeetat voivat levitä ihmiselimistössä verenkierron mukana useisiin kudoksiin aiheuttaen oireita muun muassa nivelissä, sydämessä ja hermostossa. Keskushermostoon levinnyttä infektiota kutsutaan Lymen neuroborrelioosiksi. Neuroborrelioosin diagnostiikka perustuu potilaan neurologisiin oireisiin sekä solumäärän ja Borrelia-spesifisten vasta-aineiden määritykseen aivoselkäydinnesteestä. Hiljattain myös kemokiini CXCL13 on otettu käyttöön Lymen neuroborrelioosin diagnostiikan biomarkkeriksi. Tämän tutkimuksen tarkoituksena oli selvittää Borrelia-bakteerin virtauksen alla tapahtuvan endoteelisitoutumisen rooli infektion patogeneesissä, tutkia infektion leviämistä eri kudoksiin in vivo -kuvantamisen avulla hiirimallissa ja tutkia sytokiinien käyttöä Lymen neuroborrelioosin diagnostisina biomarkkereina. Tutkimuksessa havaittiin, että Borrelia-bakteerin dekoriinia sitovat proteiinit sitoutuvat myös biglykaaniin, joka on dekoriinia yleisempi proteoglykaani verisuonten endoteelin pinnalla. Tämän biglykaani-interaktion avulla Borrelia kykenee sitoutumaan verisuonten endoteeliin nestevirtauksen aiheuttaman vastuksen alla. Lisäksi tutkimuksessa selvisi, että Borrelia-infektion kulkua voi kuvantaa elävässä eläimessä positroniemissiotomografian avulla. Tutkimuksessa havaittiin myös, että CXCL13 on soveltuvin sytokiini Lymen neuroborrelioosin diagnostiikan biomarkkeriksi ja että CXCL13:n pitoisuus voidaan määrittää potilaan aivoselkäydinnesteestä pikatestin avulla, mikä nopeuttaa huomattavasti tautidiagnostiikkaa. Kaiken kaikkiaan tutkimustulokset paljastivat tärkeää uutta tietoa Borrelia-infektion patogeneesistä ja auttavat Lymen borrelioosin diagnostiikan kehittämisessä

Borrelia burgdorferi specific serum and cerebrospinal fluid antibodies in Lyme neuroborreliosis

Publisher Copyright: © 2022 The Author(s)We used definite Lyme neuroborreliosis (LNB) adult patient acute and convalescent phase serum (n = 63 and 61, respectively) and cerebrospinal fluid (CSF; acute n = 63, 3 weeks timepoint n = 41) samples to characterize Borrelia burgdorferi specific antibody responses in patient subgroups categorized by demographics, infection manifestation and phase, infecting B. burgdorferi genospecies, received antibiotic treatments, and treatment outcome. B. burgdorferi antibodies were analyzed using 4 different assays incorporating a large array of antigens. We observed that B. burgdorferi specific serum antibodies show a universal, antigen independent declining trend after antibiotic treatment of LNB at 1 year. Antibodies declined similarly among women and men over time, and the decline was independent of patient age. The antibody responses were independent of the predominant LNB manifestation, treatment received by the patient, infecting B. burgdorferi genospecies, or the subjective improvement experienced by the patients. Finally, the antibody specificities in CSF reflected the specificities observed in serum samples.Peer reviewe

C6 peptide enzyme immunoassay in Lyme borreliosis serology

The cut-off values used in C6 peptide-based enzyme immunoassay (EIA), a widely used test in Lyme borreliosis (LB) serology, have not been thoroughly analysed. The objective of the study was to examine the performance of the C6 EIA, and to determine optimal cut-off values for the test. The analysed data contained results of 1368 serum samples. C6 EIA index values were compared statistically with the immunoblot (IB) test results. The identified cut-off values were further tested in a well-defined LB patient cohort. Cut-off value 1.6 appeared to be optimal when C6 EIA was used as a stand-alone test. When using C6 EIA as the first-tier test, the optimal cut-off values were 0.9 and 2.4 for negative and positive results. When C6 EIA was used as a second-tier test, samples yielding C6 index values >= 3.0 could be considered positive. The identified cut-off values had also a high sensitivity to identify seropositivity among definite LB patients. The identified cut-off values refine the role of C6 EIA in LB serology. Importantly, the use of C6 EIA leads to a reduction in the number of samples that need to be analysed using an IB, thus also reducing the costs. Two alternative workflows for LB serology including the C6 EIA are suggested.Peer reviewe

Clinical performance and analytical accuracy of a C6 peptide-based point-of-care lateral flow immunoassay in Lyme borreliosis serology

We evaluated the analytical accuracy and the clinical performance of a ReaScan+ C6 LYME IgG point-of-care immunoassay (Reagena; index test). Analytical accuracy was evaluated in comparison to a C6 Lyme ELISA™ reference method (Oxford Immunotec) with retrospectively identified serum and CSF samples. The clinical performance was evaluated by using Lyme borreliosis patient and control subject serum and CSF samples. The study was conducted by following the 2015 Standards for Reporting of Diagnostic Accuracy Studies procedure. The sensitivity and specificity of the index test with serum samples were 83% and 91.6%, respectively, when C6 Lyme ELISA™ was used as a reference. The clinical sensitivity of the index test was 97.2%/96.8% for identifying Borrelia specific antibodies in definite/possible Lyme neuroborreliosis. With CSF samples, the clinical sensitivity was 97.2% for definite and 87.1% for possible Lyme neuroborreliosis. The clinical specificity of the assay was 96.1% with serum and 100% with CSF samples.</p

Perceived interest in learning sustainability competencies among higher education students

Authors are listed alphabeticallyPurpose This study aims to assess higher education students’ interest in learning sustainability competencies and their pro-ecological worldviews at a large research-intensive university in Finland to provide a background information for developing a sustainability science course. Design/methodology/approach In total, 797 students participated in the study. The data were collected through an online survey that measured students’ interest in learning sustainability competencies and their pro-ecological worldviews. Participants were classified into five categories based on field of study. The data were analysed by using Pearson’s correlation, independent samples t-tests, and analysis of variance. Findings The participating students perceived learning of critical thinking and values thinking most interesting. Interest in learning sustainability competencies and pro-ecological worldview appeared to differ across fields of study. Participants studying humanities expressed lower interest in collaborative use of digital technology compared to the participating students in science and agriculture. Participating students in health and welfare scored lower on interest in learning values thinking than students in other study fields. Research limitations/implications The response rate was low. It is likely that the participants felt strongly about sustainability challenges, therefore making them more interested in sustainability competencies. The limited number of sustainability competencies studied does not allow generalisation to all sustainability competencies. Practical implications The differences in interest in learning sustainability competencies and pro-ecological worldview should be understood and considered when planning sustainability education. Originality/value These results provide new insights into the interlinkage of students’ interest in learning sustainability competencies, their pro-ecological worldviews and their field of study.Peer reviewe

The effects of Borrelia infection on its wintering rodent host

In seasonal environments, appropriate adaptations are crucial for organisms to maximize their fitness. For instance, in many species, the immune function has been noticed to decrease during winter, which is assumed to be an adaptation to the season's limited food availability. Consequences of an infection on the health and survival of the host organism could thus be more severe in winter than in summer. Here, we experimentally investigated the effect of a zoonotic, endemic pathogen, Borrelia afzelii infection on the survival and body condition in its host, the bank vole (Myodes glareolus), during late autumn-early winter under semi-natural field conditions in 11 large outdoor enclosures. To test the interaction of Borrelia infection and energetic condition, four populations received supplementary nutrition, while remaining seven populations exploited only natural food sources. Supplementary food during winter increased the body mass independent of the infection status, however, Borrelia afzelii infection did not cause severe increase in the host mortality or affect the host body condition in the late autumn-early winter. While our study suggests that no severe effects are caused by B. afzelii infection on bank vole, further studies are warranted to identify any potentially smaller effects the pathogen may cause on the host fitness over the period of whole winter

Borrelia burgdorferi specific serum and cerebrospinal fluid antibodies in Lyme neuroborreliosis

We used definite Lyme neuroborreliosis (LNB) adult patient acute and convalescent phase serum (n = 63 and 61, respectively) and cerebrospinal fluid (CSF; acute n = 63,3 weeks timepoint n = 41) samples to characterize Borrelia burgdorferi specific antibody responses in patient subgroups categorized by demographics, infection manifestation and phase, infecting B. burgdorferi genospecies, received antibiotic treatments, and treatment outcome. B. burgdorferi antibodies were analyzed using 4 different assays incorporating a large array of antigens. We observed that B. burgdorferi specific serum antibodies show a universal, antigen independent declining trend after antibiotic treatment of LNB at 1 year. Antibodies declined similarly among women and men over time, and the decline was independent of patient age. The antibody responses were independent of the predominant LNB manifestation, treatment received by the patient, infecting B. burgdorferi genospecies, or the subjective improvement experienced by the patients. Finally, the antibody specificities in CSF reflected the specificities observed in serum samples.</p

C6 peptide enzyme immunoassay in Lyme borreliosis serology

The cut-off values used in C6 peptide-based enzyme immunoassay (EIA), a widely used test in Lyme borreliosis (LB) serology, have not been thoroughly analysed. The objective of the study was to examine the performance of the C6 EIA, and to determine optimal cut-off values for the test. The analysed data contained results of 1368 serum samples. C6 EIA index values were compared statistically with the immunoblot (IB) test results. The identified cut-off values were further tested in a well-defined LB patient cohort. Cut-off value 1.6 appeared to be optimal when C6 EIA was used as a stand-alone test. When using C6 EIA as the first-tier test, the optimal cut-off values were 0.9 and 2.4 for negative and positive results. When C6 EIA was used as a second-tier test, samples yielding C6 index values ≥3.0 could be considered positive. The identified cut-off values had also a high sensitivity to identify seropositivity among definite LB patients. The identified cut-off values refine the role of C6 EIA in LB serology. Importantly, the use of C6 EIA leads to a reduction in the number of samples that need to be analysed using an IB, thus also reducing the costs. Two alternative workflows for LB serology including the C6 EIA are suggested.</p

Targeting of vascular adhesion protein-1 by positron emission tomography visualizes sites of inflammation in Borrelia burgdorferi-infected mice

Background: In the present study, we sought to evaluate the feasibility of targeting vascular adhesion protein-1 (VAP-1) by positron emission tomography (PET) for the longitudinal quantitative assessment of Borrelia burgdorferi infection-induced inflammation in mice.Methods: Mice with B. burgdorferi infection-induced arthritis were studied. During a 7-week follow-up period, the progression of arthritis was monitored weekly with 68Ga-DOTA-Siglec-9 PET/computed tomography (CT) and measurement of tibiotarsal joint swellings. A subgroup of infected mice was treated with ceftriaxone. Finally, histopathological assessment of joint inflammation was performed and VAP-1 expression in joints were determined.Results: Explicit joint swelling and 68Ga-DOTA-Siglec-9 uptake could be demonstrated in the affected joints from B. burgdorferi-infected mice. By contrast, no obvious accumulation of 68Ga-DOTA-Siglec-9 was detected in joints of uninfected mice. The maximum swelling and highest uptake in the affected joints were observed 4 weeks after the infection. 68Ga-DOTA-Siglec-9 uptake in joints correlated with joint swelling (P < 0.0001) and histopathological scoring of inflammation (P = 0.020). Despite short-term antibiotic treatment, the arthritis persisted, and the PET signal remained as high as in nontreated mice. Immunohistochemistry revealed strong-to-moderate expression of VAP-1 in the synovium of B. burgdorferi-infected mice, while only weak expression of VAP-1 was detected in uninfected mice.Conclusions: The present study showed that 68Ga-DOTA-Siglec-9 can detect B. burgdorferi infection-induced arthritis in mice. Furthermore, longitudinal PET/CT imaging allowed monitoring of arthritis development over time

Conserved lysine residues in decorin binding proteins of Borrelia garinii are critical in adhesion to human brain microvascular endothelial cells

Lyme borreliosis is a tick-borne disease caused by Borrelia burgdorferi sensu lato spirochetes (Lyme borreliae). When the disease affects the central nervous system, it is referred to as neuroborreliosis. In Europe, neuroborreliosis is most often caused by Borrelia garinii. Although it is known that in the host Lyme borreliae spread from the tick bite site to distant tissues via the blood vasculature, the adherence of Lyme borreliae to human brain microvascular endothelial cells has not been studied before. Decorin binding proteins are adhesins expressed on Lyme borreliae. They mediate the adhesion of Lyme borreliae to decorin and biglycan, and the lysine residues located in the binding site of decorin binding proteins are important to the binding activity. In this study, we show that lysine residues located in the canonical binding site can also be found in decorin binding proteins of Borrelia garinii, and that these lysines contribute to biglycan and decorin binding. Most importantly, we show that the lysine residues are crucial for the binding of Lyme borreliae to decorin and biglycan expressing human brain microvascular endothelial cells, which in turn suggests that they are involved in the pathogenesis of neuroborreliosis.</p