Circular mitochondrial-encoded mRNAs are a distinct subpopulation of mitochondrial mRNA in Trypanosoma brucei

Since the first identification of circular RNA (circRNA) in viral-like systems, reports of circRNAs and their functions in various organisms, cell types, and organelles have greatly expanded. Here, we report the first evidence, to our knowledge, of circular mRNA in the mitochondrion of the eukaryotic parasite, Trypanosoma brucei. While using a circular RT-PCR technique developed to sequence mRNA tails of mitochondrial transcripts, we found that some mRNAs are circularized without an in vitro circularization step normally required to produce PCR products. Starting from total in vitro circularized RNA and in vivo circRNA, we high-throughput sequenced three transcripts from the 3' end of the coding region, through the 3' tail, to the 5' start of the coding region. We found that fewer reads in the circRNA libraries contained tails than in the total RNA libraries. When tails were present on circRNAs, they were shorter and less adenine-rich than the total population of RNA tails of the same transcript. Additionally, using hidden Markov modelling we determined that enzymatic activity during tail addition is different for circRNAs than for total RNA. Lastly, circRNA UTRs tended to be shorter and more variable than those of the same transcript sequenced from total RNA. We propose a revised model of Trypanosome mitochondrial tail addition, in which a fraction of mRNAs is circularized prior to the addition of adenine-rich tails and may act as a new regulatory molecule or in a degradation pathway.

Circular mitochondrial-encoded mRNAs are a distinct subpopulation of mitochondrial mRNA in Trypanosoma brucei

Since the first identification of circular RNA (circRNA) in viral-like systems, reports of circRNAs and their functions in various organisms, cell types, and organelles have greatly expanded. Here, we report the first evidence of circular mRNA in the mitochondrion of the eukaryotic parasite, Trypanosoma brucei . While using a circular RT-PCR technique developed to sequence mRNA tails of mitochondrial transcripts, we found that some mRNAs are circularized without an in vitro circularization step normally required to produce PCR products. Starting from total in vitro circularized RNA and in vivo circRNA, we high-throughput sequenced three transcripts from the 3' end of the coding region, through the 3' tail, to the 5' start of the coding region. We found that fewer reads in the circRNA libraries contained tails than in the total RNA libraries. When tails were present on circRNAs, they were shorter and less adenine-rich than the total population of RNA tails of the same transcript. Additionally, using hidden Markov modelling we determined that enzymatic activity during tail addition is different for circRNAs than for total RNA. Lastly, circRNA UTRs tended to be shorter and more variable than those of the same transcript sequenced from total RNA. We propose a revised model of Trypanosome mitochondrial tail addition, in which a fraction of mRNAs is circularized prior to the addition of adenine-rich tails and may act as a new regulatory molecule or in a degradation pathway.

Circular mitochondrial-encoded mRNAs are a distinct subpopulation of mitochondrial mRNA in Trypanosoma brucei

Since the first identification of circular RNA (circRNA) in viral-like systems, reports of circRNAs and their functions in various organisms, cell types, and organelles have greatly expanded. Here, we report the first evidence of circular mRNA in the mitochondrion of the eukaryotic parasite, Trypanosoma brucei . While using a circular RT-PCR technique developed to sequence mRNA tails of mitochondrial transcripts, we found that some mRNAs are circularized without an in vitro circularization step normally required to produce PCR products. Starting from total in vitro circularized RNA and in vivo circRNA, we high-throughput sequenced three transcripts from the 3' end of the coding region, through the 3' tail, to the 5' start of the coding region. We found that fewer reads in the circRNA libraries contained tails than in the total RNA libraries. When tails were present on circRNAs, they were shorter and less adenine-rich than the total population of RNA tails of the same transcript. Additionally, using hidden Markov modelling we determined that enzymatic activity during tail addition is different for circRNAs than for total RNA. Lastly, circRNA UTRs tended to be shorter and more variable than those of the same transcript sequenced from total RNA. We propose a revised model of Trypanosome mitochondrial tail addition, in which a fraction of mRNAs is circularized prior to the addition of adenine-rich tails and may act as a new regulatory molecule or in a degradation pathway.

Staphylococcus aureus bacteremia in Danish patients with cardiac implantable electronic devices: an explorative epidemiological study

Background

Device-related infection is the most common serious complication in patients with cardiac implantable electronic devices (CIED). Staphylococcus aureus accounts for up to 30% of CIED-related infections. There is a lack of scientific literature investigating risk of Staphylococcus aureus bacteremia (SAB) in CIED-patients.

Purpose

We aimed to describe the risk of SAB in Danish patients with a CIED through the years 2000–2018 compared to the background population.

Methods

Patients who received a CIED from 2000–2018 were identified from The Danish National Pacemaker and ICD Register. Patients were matched 1:5 on age and gender with the background population. We identified the primary endpoint of first time SAB from The National Danish Staphylococcus Aureus Bacteremia Database. The cumulative incidence of SAB was calculated using the Aalen-Johansen estimator, adding competing risk of death into account. Hazard ratios were estimated by Cox regression models adjusting for age and gender. Crude rates of relapse SAB, defined as a new SAB episode 14–180 days after first SAB, and device extractions were reported for all patients who survived 14 days from SAB diagnosis.

Results

We identified 79,324 CIED-patients (pacemaker (PM) = 61,227; Implantable Cardioverter Defibrillator (ICD) = 11,635; Cardiac resynchronization therapy, PM or ICD (CRT) = 6,364 and 396,590 matched controls (median age 75.5±13.3 years; 61% males). Age and gender distribution differed significantly by device type (age: PM 76.1±12.1; ICD 62.4±13.4; CRT 68.0±11.1; males: PM: 55.6%, ICD% 75.5: CRT: 80.9%). Across a mean follow-up of 5.9 (±4.6) years, we observed first episode of SAB in 1,430 (1.8%) CIED-patients, compared to 2,599 (0.7%) patients in the control population (p<0.001).

The 10-year cumulative incidence of SAB was 1.0% for controls and 2.2% for CIED patients. The risk of SAB differed substantially by device type (Figure 1). Compared to controls and adjusted for age and gender, increasing hazard ratios for SAB were observed with more advanced devices: PM 1.12 (1.11–1.13); ICD 1.36 (1.33–1.39); CRT 1.55 (1.51–1.59). However, CIED-patients with SAB did not have higher 30-day mortality rates than the non-CIED control population with SAB (Controls 34.8%; PM 35.1%; ICD 28.1% CRT 26.1%, p=0.016). Out of all SAB patients who survived 14 days from SAB diagnosis (Controls=1,672; CIED=1,107), relapse SAB occurred in 52 (3.1%) controls and in 51 (4.6%) CIED-patients (PM 4.0%; ICD 5.8%; CRT 6.3%). Device extraction within 14 and 30 days from SAB diagnosis was undertaken in less than 30% of the CIED-patients (PM: 11.3/13.6%; ICD: 22.7/27.5%; CRT: 17.4/20.1%).

Conclusion

The occurrence of SAB was higher in CIED patients compared with controls and increased with more advanced devices. There was no difference in 30-day mortality after SAB between CIED patients and controls. Relapse SAB occurred in less than 7%, despite a low percentage of early device extractions.

Funding Acknowledgement

Type of funding sources: None.

POS1301 OCCURRENCE OF ARTHRITIS IS IN 37% OF THE PATIENTS WITHOUT OVERLYING SKIN INVOLVEMENT IN JUVENILE LOCALIZED SCLERODERMA. SUMMARY OF THE EXTRACUTANEOUS INVOLVEMENT IN A MONOCENTRIC COHORT

Background

Localized scleroderma in childhood (locSSc) occurs with a prevalence of 3.2 to 3.6 per 10 000 children1. There are not many publications assessing in detail the extracutaneous manifestations (EM) of locSSc. It is very important to assess the EM too, because the EM can lead to significant damage and morbidity too.

Objectives

To assess the occurrence of extracutaneous manifestations in locSSc in our cohort and the correlation of the occurring EM to the subtype of locSSc and the localisation of the skin involvement.

Methods

Retrospective chart review of all consecutive patients, who were followed at our centre from January 2000 to July 2020 with the diagnosis of locSSc. The subtype was classified according Laxer et al2. The patients were under the age of 18 years at the time point of the first visit. Demographic and clinical data were extracted.

Results

73 patients could be identified, 71% of them were female. Mean age at disease onset was 8 years (4-14 years). The mean time of follow up was 5 years. The subtype distribution was 42 (57%) linear, 24 (33%) mixed, 6 (8%) circumscribed morphea and 1 (1%) pansclerotic morphea. 9 (21%) of the 42 patients with linear subtype had coup de sabre and 4 (10%) of them had Parry Romberg. Fifty six (76%) patients had EM, 40 (53%) of them had 1 form of EM, 10 (13%) of them 2 forms of EM and 6 (8%) patients 3 forms of EM. 53(73%) of the 76 patients had arthritis. Twenty (37%) of the 53 arthritis involvement occurred on a localisation without overlaying skin involvement. Most frequent localisation of arthritis without overlaying skin involvement was in the hip joints (18%). Of the 53 patients with articular involvement had 31 (58%) linear, 17 (32%) mixed, 4 (7.5) circumscribed morphea and 1 (2%) pansclerotic subtype. 14 (19%) of the 73 had length discrepancy of the extremities and 13 (93%) of them had linear subtype. Neurologic symptoms presenting as headache occurred in 8 (11%) patients, 6 (75%) of them had Parry Romberg subtype and 2 (25%) of them coup de sabre. “White” anterior uveitis was screened according to published recommendations3,4 and it occurred in 3 patients, only one of them had coup the sabre the other two linear and mixed subtype without involvement of the face.

Conclusion

EM is very common and it occurs in 76% of the patients. Thirty seven percent of the articular involvement occurred in joints without overlaying skin involvement, which suggest the importance of the whole body joint count as in juvenile idiopathic arthritis. Only 1 of 3 patients with uveitis had skin involvement in the face, which emphasize the recommended uveitis screening.

References

[1]Beukelman T, Xie F, Foeldvari I. The prevalence of localised scleroderma in childhood assessed in the administrative claims data from the United States. Journal of Scleroderma and Related Disorders 2018;I-2.

[2]Laxer RM, Zulian F. Localized scleroderma. Curr Opin Rheumatol 2006;18(6):606-13. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17053506).

[3]Constantin T, Foeldvari I, Pain CE, et al. Development of minimum standards of care for juvenile localized scleroderma. Eur J Pediatr 2018;177(7):961-977. DOI: 10.1007/s00431-018-3144-8.

[4]Zulian F, Culpo R, Sperotto F, et al. Consensus-based recommendations for the management of juvenile localised scleroderma. Ann Rheum Dis 2019;78:1019-1024. DOI: 10.1136/annrheumdis-2018-214697.

Disclosure of Interests

None declared

POS0606 HOW DO GLUCOCORTICOIDS, BIOLOGIC DISEASE-MODIFYING ANTI-RHEUMATIC DRUGS AND DISEASE ACTIVITY IMPACT THE RISK OF STAPHYLOCOCCUS AUREUS BACTEREMIA IN RHEUMATOID ARTHRITIS PATIENTS? A NATIONWIDE NESTED CASE CONTROL STUDY IN THE DANISH DANBIO COHORT

Background

Staphylococcus aureus bacteremia (SAB) has high mortality and rheumatoid arthritis (RA) patients are at increased risk,[1] however, the role of anti-rheumatic treatments and disease activity is unclear.[2,3]

Objectives

To explore the impact of treatment with glucocorticoids and biologic disease-modifying anti-rheumatic drugs (bDMARDs) and disease activity on the risk of SAB in RA patients.

Methods

Nested case control study in a nationwide cohort of RA patients (DANBIO) with no history of SAB. Cases had a first-time microbiologically verified SAB between 2010-2018. Controls were incidence density matched (age and sex) at time of SAB (index date). We linked data from DANBIO (e.g. disease activity, anti-rheumatic treatment) to other national registries (comorbidities, prescriptions, socioeconomic status, etc). Treatments were redeemed prescriptions or registrations in DANBIO (oral glucocorticoids, bDMARDs) 0-2 years before the index date. Dose of oral glucocorticoids was retrieved from either DANBIO or estimated from the latest prescription. Risk associated with treatment and disease activity was assessed by multivariate conditional logistic regression. For treatments, excess cases/10,000 exposed/year were calculated by multiplying the fully adjusted OR (95%CI) with the incidence rate in the cohort. Missing data was handled by multiple imputation.

Results

We identified 180 cases in 30,479 RA patients (IR 106.7/100,000 person-years) and matched 720 controls (53% women, median age 73 years, IQR 65;80). For cases, orthopedic implants were frequent (53%/34% for cases/controls), many had recent surgery (38%/5%), longstanding RA (13 years (6;21)/8 (4;14)), joint erosions (48%/39%), moderate (29%/16%) or high (10%/7%) disease activity, and used glucocorticoids (41%/19%) and bDMARDs (31%/20%). Adjusted ORs were high for current use of oral glucocorticoids, especially for doses >10mg/day (OR=14.5 (4.0; 52.2)). For bDMARDs, adjusted OR was 1.9 (1.1; 3.2). Correspondingly, the treatments increased risk with 144 and 9 excess cases/10,000/year, respectively (Table 1). For disease activity, adjusted ORs were >1 (non-significant) for moderate and high disease activity compared with remission (Figure 1).

Figure 1.

Disease activity and risk of Staphylococcus aureus bacteremia

Table 1.

Use of oral glucocorticoids and biologic disease-modifying anti-rheumatic drugs (bDMARDs) 0-2 years before the index date and risk of Staphylococcus aureus bacteremia (SAB)

SAB cases,n=180Controls, n=720OR (95% CI)*Number of excess cases/10,000 exposed/year (confidence limits)Glucocorticoidsn (%)n (%)No67 (37)450 (63)refYes113 (63)270 (38)2.4 (1.5; 3.8)15 (6; 30) Former usera39 (22)133 (19)1.7 (0.9; 3.0)NA Current userb74 (41)137 (19)3.2 (1.9; 5.3)23 (9; 46)Current daily dose >0-5 mg44 (24)108 (15)2.1 (1.1; 3.8)11 (1; 30) >5-10mg18 (10)26 (4)3.5 (1.4; 8.6)26 (4; 81) >10mg12 (7)8 (1)14.5 (4.0; 52.2)144 (32; 46)bDMARDsNo111 (62)558 (78)refYes69 (38)162 (23)1.9 (1.1; 3.2)10 (1; 24) Former usera14 (8)18 (3)2.1 (0.8; 5.8)NA Current userb55 (31)144 (20)1.9 (1.1; 3.2)9 (1; 23)

a >3 to 24 months before (rituximab >12 to 24 months), b 0-3 months before (rituximab 0-12 months)

*adjusted for sex, age, comorbidities, implants, recent surgery, RA disease duration, time since entry, csDMARDs, socioeconomic-, sero-, erosive-, functional- and smoking status, body mass index, and disease activity (high/low/moderate/remission)

Conclusion

Oral glucocorticoids and bDMARDs increased relative risk of SAB, with number of excess cases being high for oral glucocorticoids (>10 mg/day) and low for bDMARDs. Disease activity had minor impact on the risk. This emphasizes that high dose glucocorticoids should be used with caution.

References

[1] Dieperink SS, resubmitted after revision Jan 2022

[2]Smit J et al. 2016 doi:10.1016/j.mayocp.2016.04.023

[3]Sams M et al. 2015 doi:10.1007/s00296-015-3239-8

Acknowledgements

We wish to acknowledge the valuable inputs from patient representative Pia Lüchau Pedersen who participated in the initial brainstorming phase that led to the hypotheses being tested in this study

Disclosure of Interests

None declared

Risk of Staphylococcus aureus bacteraemia in patients with rheumatoid arthritis and the effect of orthopaedic implants on the risk: a nationwide observational cohort study

OBJECTIVE

It remains disputed how much the risk of Staphylococcus aureus bacteraemia (SAB) is increased in patients with rheumatoid arthritis (RA), and the extent to which orthopaedic implants explain the risk. We assessed SAB incidence rates (IRs) and incidence rate ratios (IRRs), comparing RA patients with a general population cohort (GPC) and individuals with versus without orthopaedic implants.

METHOD

Danish residents aged ≥ 18 years without prior RA or SAB (=GPC) were followed up for RA and microbiologically verified SAB events (1996-2017). IRRs were calculated by age- and sex-stratified Poisson regression adjusted for age, comorbidities, calendar year, and socioeconomic status.

RESULTS

The GPC comprised 5 398 690 individuals. We identified 33 567 incident RA patients (=RA cohort) (median follow-up 7.3 years, IQR 3.6-12.3). We observed 25 023 SAB events (n = 224 in the RA cohort). IRs per 100 000 person-years were 81.0 (RA cohort) and 29.9 (GPC). IRs increased with age. Adjusted IRRs in 18-59-year-old RA patients were 2.6 (95% confidence interval 1.8-3.7) for women and 1.8 (1.1-3.1) for men, compared with same sex and age group GPC. IRRs declined with age. Compared with the GPC without implants, IRRs for RA patients with implants ranged from 1.9 (1.3-2.8) (women ≥ 70 years) to 5.3 (2.2-12.8) (18-59-year-old men).

CONCLUSION

In this nationwide registry-based cohort study RA was a risk factor for SAB, and orthopaedic implants further increased the risk. Clinicians should be aware of potential SAB in patients with RA and orthopaedic implants.

Partial separability and functional graphical models for multivariate Gaussian processes

The covariance structure of multivariate functional data can be highly complex, especially if the multivariate dimension is large, making extensions of statistical methods for standard multivariate data to the functional data setting challenging. For example, Gaussian graphical models have recently been extended to the setting of multivariate functional data by applying multivariate methods to the coefficients of truncated basis expansions. However, compared with multivariate data, a key difficulty is that the covariance operator is compact and thus not invertible. This paper addresses the general problem of covariance modelling for multivariate functional data, and functional Gaussian graphical models in particular. As a first step, a new notion of separability for the covariance operator of multivariate functional data is proposed, termed partial separability, leading to a novel Karhunen–Loève-type expansion for such data. Next, the partial separability structure is shown to be particularly useful in providing a well-defined functional Gaussian graphical model that can be identified with a sequence of finite-dimensional graphical models, each of identical fixed dimension. This motivates a simple and efficient estimation procedure through application of the joint graphical lasso. Empirical performance of the proposed method for graphical model estimation is assessed through simulation and analysis of functional brain connectivity during a motor task.

SAT0062 INCIDENCE OF STAPHYLOCOCCUS AUREUS BACTEREMIA IN PATIENTS WITH RHEUMATOID ARTHRITIS: A NATIONWIDE COHORT STUDY

Background:

Staphylococcus aureusis a frequent cause of bacteremia (SAB) associated with high mortality and morbidity. Patients with rheumatoid arthritis (RA) are at increased risk of septic arthritis and prosthetic joint infection withS. aureus.

Objectives:

To assess the incidence rate (IR) of first-time SAB in patients with RA and to estimate the incidence rate ratio (IRR) of SAB with a general population cohort without RA serving as the reference.

Methods:

Individuals with no prior history of SAB or RA were included consecutively from 31 December 1996, their 18th birthday or date of immigration, whichever came latest, and followed until first-time SAB, death, emigration or 31 December 2017, whichever came first. Information on RA diagnosis, vital status, age, sex, place of residence, comorbidities, medication and first-time SAB were achieved on an individual level through cross-linkage between five virtually complete Danish nationwide registries (Civil Registration System, National Patient Registry, Register of Medicinal Product Statistics, DANBIO rheumatology registry and the SAB database). We used Poisson regression to estimate adjusted IRRs overall and stratified by age and sex.

Results:

In total, 6,127,150 individuals were included of whom 34,627 individuals developed RA. In the RA cohort, 228 first-time SAB events occurred during 283,186 person years (PY) of follow-up (IR 80.5/100,000 PY) compared with 25,268 events during 87,521,120 PY of follow-up in the general population cohort (IR 28.9/100,000 PY). Median follow-up was 7.2 years (IQR 3.5-12.3) after RA diagnosis and 18.7 years (IQR 6.8-21) in the general population cohort. Individuals with RA who developed SAB were more often women, had an orthopaedic implant and had recent use of glucocorticoids compared with individuals with SAB without RA. (Table 1) IRs of SAB were higher among patients with RA compared with the general population in all age categories. The IRs increased with age and were higher in men, both in patients with RA and in the general population cohort. After adjustment, the IRR remained higher for individuals younger than 70 years with RA compared with the general population but was similar for older individuals. (Figure 1)

Conclusion:

In this nationwide cohort with more than 25,000 observed first-time SAB events, patients with RA younger than 70 years old had a 1.5-2 times higher incidence rate compared with the general population. The significance of anti-rheumatic treatments on risk and the prognosis of SAB in patients with RA remain to be explored.

Acknowledgments:

We wish to thank patient representative Pia Lüchau Pedersen

Disclosure of Interests:

Sabine Dieperink: None declared, Bente Glintborg Grant/research support from: Grants from Pfizer, Biogen and Abbvie, Louise Bruun Oestergaard: None declared, Mette Nørgaard: None declared, Thomas Benfield Grant/research support from: Pfizer, Novo Nordisk and GSK, Frank Mehnert: None declared, Andreas Petersen: None declared, Merete L. Hetland Grant/research support from: BMS, MSD, AbbVie, Roche, Novartis, Biogen and Pfizer, Consultant of: Eli Lilly, Speakers bureau: Orion Pharma, Biogen, Pfizer, CellTrion, Merck and Samsung Bioepis

Increased risk of incident primary cancer after Staphylococcus aureus bacteremia: A matched cohort study

Susceptibility to infectious disease may be a marker of immunodeficiency caused by unrecognized cancer. To test the hypothesis, the risk of incident primary cancer was estimated among survivors of Staphylococcus aureus bacteremia (SAB) and compared to a random population cohort.Nation-wide population-based matched cohort study. Cases of SAB were identified from a national database and incident primary cancers were ascertained by record linkage. Incidence rate (IR) and ratio (IRR) with 95% confidence interval (CI) of 27 cancers was calculated by Poisson regression.During the first year of follow-up, 165 and 943 incident cases of cancer occurred in the case cohort (n = 12,918 (1.3%)) and the population cohort (n = 117,465 (0.8%)) for an IR of 3.78 (3.22-4.40) and 2.28 (2.14-2.43) per 100,000 person-years. The IRR was 1.65 (1.40-1.95). Of 27 cancers, 7 cancers occurred more frequently amongst cases than controls: cervical cancer (IRR 37.83 (4.23-338.47)), multiple myeloma (IRR 6.31 (2.58-15.44)), leukemia (IRR 4.73 (2.21-10.10)), sarcoma (IRR 4.73 (1.18-18.91)), liver cancer (IRR 3.64 (1.30-10.21)), pancreatic cancer (IRR 2.8 (1.27-6.16)), and urinary tract cancer (IRR 2.58 (1.23-5.39)). Compared to the control population, the risk of cancer was higher for those without comorbidity and with younger age. The overall risk of cancer during 2 to 5 years of follow-up was not increased (IRR 0.99 (95% CI: 0.89-1.11). However, the risk of pharyngeal cancer was increased (IRR 1.88 (1.04-3.39)) and the risk of liver cancer remained increased (IRR 3.93 (2.36-6.55)).The risk of primary incident cancer was 65% higher in the SAB cohort compared to the population cohort during the first year of follow-up and included 7 specific cancers. The risk was higher for those without comorbidity and with younger age. Screening for these specific cancers in selected populations may allow for earlier detection.

Surface tension determines tissue shape and growth kinetics

The collective self-organization of cells into three-dimensional structures can give rise to emergent physical properties such as fluid behavior. Here, we demonstrate that tissues growing on curved surfaces develop shapes with outer boundaries of constant mean curvature, similar to the energy minimizing forms of liquids wetting a surface. The amount of tissue formed depends on the shape of the substrate, with more tissue being deposited on highly concave surfaces, indicating a mechano-biological feedback mechanism. Inhibiting cell-contractility further revealed that active cellular forces are essential for generating sufficient surface stresses for the liquid-like behavior and growth of the tissue. This suggests that the mechanical signaling between cells and their physical environment, along with the continuous reorganization of cells and matrix is a key principle for the emergence of tissue shape.

Abstract P1-12-06: Endothelial dysfunction in breast cancer survivors on aromatase inhibitors (AIs) over time

Endothelial dysfunction in breast cancer survivors on aromatase inhibitors (AIs) over time

Background: AIs reduce breast cancer-related mortality however they may increase cardiovascular (CV) risk. Our previously published cross-sectional study suggested women on AIs were more likely to have endothelial dysfunction when measured by EndoPAT ratio as compared to healthy postmenopausal women. Reductions in EndoPAT ratio (<1.67) and small artery elasticity (SAE) and increases in highly sensitive C-reactive protein (CRP) are associated with worsening endothelial dysfunction and increased cardiovascular events. We present data from a longitudinal pilot study looking at endothelial dysfunction over time in women on AIs.

Methods: Fourteen women with locally advanced breast cancer prescribed an AI underwent vascular testing at baseline (pre-AI) and at 6 months. Subjects with tobacco use, hypertension or hyperlipidemia were excluded. Consented subjects underwent biomarker analysis and radial artery pulse wave analysis using the HDI/Pulse Wave CR-2000 CV Profiling System and pulse contour analysis using the Endo-PAT2000 system. Biomarkers were obtained using a fasting blood draw to evaluate the following lipids and inflammatory markers: serum ultrasensitive estradiol, serum glucose, total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglycerides (TG), CRP, plasminogen-activator 1 (PA1), and tissue-type plasminogen activator (tPA). Changes between baseline and follow-up using Wilcoxon signed-rank tests were analyzed.

Results: Mean baseline age was 59 years and median body mass index was 26.5 kg/m2. Median systolic blood pressure and total cholesterol were 120/70 mm/Hg and 228 mg/dL, respectively. Baseline ultrasensitive estradiol levels were 7 pg/mL and hsCRP was 2.45 mg/dL. Prior to AI therapy, endoPAT ratio was 2.18 (1.19, 2.43). After six months, EndoPAT ratio declined to a median 1.12 (0.85, 1.86) (p=0.045). There were no statistically significant changes in serum glucose, TC, LDL, HDL, hsCRP, PA1 and tPA. HsCRP remained elevatedat median 2.98 mg/L. At six months, estradiol levels decreased to a median of 2 pg/mL (p=0.052), however, there appeared to be no linear association between changes in EndoPAT and estradiol (p=0.91).

Conclusion: Breast cancer survivors on AIs have endothelial dysfunction, a predictor of adverse CV disease. These changes develop while on AIs. Underlying pathophysiology requires further evaluation.

Cardiovascular markersMeasuresBaselineFollow-Up at 6 MonthsChangeP-valueBMI (kg/m2)26.5 (24.4, 31.6)27.1 (23.9, 32.9)0.5 (0.0, 1.3)0.056SBP (mmHg)120 (115, 124)123 (114, 127)-0.8 (-7.4, 3.6)0.91DBP (mmHg)70 (61, 73)69 (62, 71)0.0 (-3.0, 2.6)0.88Total Cholesterol (mg/dL)228 (202, 244)213 (210, 229)-1 (-18, 27)0.70HDL (mg/dL)64 (58, 69)73 (61, 77)2 (-3, 14)0.44LDL (mg/dL)143 (121, 159)129 (120, 142)6 (-11, 14)0.65Estradiol (pg/mL)7 (4, 15)2 (2, 3)-8 (-12, -3)0.05hsCRP (mg/dL)2.45 (1.14, 6.07)2.98 (0.90, 4.81)-8 (-12, -3)0.85EndoPAT Ratio2.18 (1.19, 2.43)1.12 (0.85, 1.86)-0.16 (-1.45, -0.02)0.0451.Summaries shown are median (1st quartile, 3rd quartile).

Citation Format: Blaes AH, Petersen A, Beckwith H, Potter D, Florea N, Yee D, Vogel R, Duprez D. Endothelial dysfunction in breast cancer survivors on aromatase inhibitors (AIs) over time [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-06.

A biomaterial with a channel-like pore architecture induces endochondral healing of bone defects

Biomaterials developed to treat bone defects have classically focused on bone healing via direct, intramembranous ossification. In contrast, most bones in our body develop from a cartilage template via a second pathway called endochondral ossification. The unsolved clinical challenge to regenerate large bone defects has brought endochondral ossification into discussion as an alternative approach for bone healing. However, a biomaterial strategy for the regeneration of large bone defects via endochondral ossification is missing. Here we report on a biomaterial with a channel-like pore architecture to control cell recruitment and tissue patterning in the early phase of healing. In consequence of extracellular matrix alignment, CD146+ progenitor cell accumulation and restrained vascularization, a highly organized endochondral ossification process is induced in rats. Our findings demonstrate that a pure biomaterial approach has the potential to recapitulate a developmental bone growth process for bone healing. This might motivate future strategies for biomaterial-based tissue regeneration.

Targeted gene sequencing and whole-exome sequencing in autopsied fetuses with prenatally diagnosed kidney anomalies

Identification of fetal kidney anomalies invites questions about underlying causes and recurrence risk in future pregnancies. We therefore investigated the diagnostic yield of next-generation sequencing in fetuses with bilateral kidney anomalies and the correlation between disrupted genes and fetal phenotypes. Fetuses with bilateral kidney anomalies were screened using an in-house-designed kidney-gene panel. In families where candidate variants were not identified, whole-exome sequencing was performed. Genes uncovered by this analysis were added to our kidney panel. We identified likely deleterious variants in 11 of 56 (20%) families. The kidney-gene analysis revealed likely deleterious variants in known kidney developmental genes in 6 fetuses and TMEM67 variants in 2 unrelated fetuses. Kidney histology was similar in the latter 2 fetuses-presenting a distinct prenatal form of nephronophthisis. Exome sequencing identified ROBO1 variants in one family and a GREB1L variant in another family. GREB1L and ROBO1 were added to our kidney-gene panel and additional variants were identified. Next-generation sequencing substantially contributes to identifying causes of fetal kidney anomalies. Genetic causes may be supported by histological examination of the kidneys. This is the first time that SLIT-ROBO signaling is implicated in human bilateral kidney agenesis.

Identification of a PVL-negative SCCmec-IVa sublineage of the methicillin-resistant Staphylococcus aureus CC80 lineage: understanding the clonal origin of CA-MRSA

OBJECTIVES

Community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) isolates belonging to clonal complex 80 (CC80) are recognized as the European CA-MRSA. The prevailing European CA-MRSA clone carries a type IVc staphylococcal cassette chromosome mec (SCCmec) and expresses Panton-Valentine leukocidin (PVL). Recently, a significant increase of PVL-negative CC80 MRSA has been observed in Denmark. The aim of this study was to examine their genetics and epidemiology, and to compare them to the European CA-MRSA clone in order to understand the emergence of PVL-negative CC80 MRSA.

METHODS

Phylogenetic analysis of the CC80 S. aureus lineage was conducted from whole-genome sequences of 217 isolates (23 methicillin-susceptible S. aureus and 194 MRSA) from 22 countries. All isolates were further genetically characterized in regard to resistance determinants and PVL carriage, and epidemiologic data were obtained for selected isolates.

RESULTS

Phylogenetic analysis revealed the existence of three distinct clades of the CC80 lineage: (a) an methicillin-susceptible S. aureus clade encompassing Sub-Saharan African isolates (n = 13); (b) a derived clade encompassing the European CA-MRSA SCCmec-IVc clone (n = 185); and (c) a novel and genetically distinct clade encompassing MRSA SCCmec-IVa isolates (n = 19). All isolates in the novel clade were PVL negative, but carried remnant parts (8-12 kb) of the PVL-encoding prophage ΦSa2 and were susceptible to fusidic acid and kanamycin/amikacin. Geospatial mapping could link these isolates to regions in the Middle East, Asia and South Pacific.

CONCLUSIONS

This study reports the emergence of a novel CC80 CA-MRSA sublineage, showing that the CC80 lineage is more diverse than previously assumed.

Cell migration on material-driven fibronectin microenvironments

Cell migration is a fundamental process involved in a wide range of biological phenomena. However, how the underlying mechanisms that control migration are orchestrated is not fully understood. In this work, we explore the migratory characteristics of human fibroblasts using different organisations of fibronectin (FN) triggered by two chemically similar surfaces, poly(ethyl acrylate) (PEA) and poly(methyl acrylate) (PMA); cell migration is mediated via an intermediate layer of fibronectin (FN). FN is organised into nanonetworks upon simple adsorption on PEA whereas a globular conformation is observed on PMA. We studied cell speed over the course of 24 h and the morphology of focal adhesions in terms of area and length. Additionally, we analysed the amount of cell-secreted FN as well as FN remodelling. Velocity of human fibroblasts was found to exhibit a biphasic behaviour on PEA, whereas it remained fairly constant on PMA. FA analysis revealed more mature focal adhesions on PEA over time contrary to smaller FAs found on PMA. Finally, human fibroblasts seemed to remodel adsorbed FN more on PMA than on PEA. Overall, these results indicate that the cell-protein-material interface affects cell migratory behaviour. Analysis of FAs together with FN secretion and remodelling were associated with differences in cell velocity providing insights into the factors that can modulate cell motility.

Mechanosensation across borders: fibroblasts inside a macroporous scaffold sense and respond to the mechanical environment beyond the scaffold walls

In tissue defects, cells face distinct mechanical boundary conditions, but how this influences early stages of tissue regeneration remains largely unknown. Biomaterials are used to fill defects but also to provide specific mechanical or geometrical signals. However, they might at the same time shield mechanical information from surrounding tissues that is relevant for tissue functionalisation. This study investigated how fibroblasts in a soft macroporous biomaterial scaffold respond to distinct mechanical environments while they form microtissues. Different boundary stiffnesses counteracting scaffold contraction were provided via a newly developed in vitro setup. Online monitoring over 14 days revealed 3.0 times lower microtissue contraction but 1.6 times higher contraction force for high vs. low stiffness. This difference was significant already after 48 h, a very early stage of microtissue growth. The microtissue's mechanical and geometrical adaptation indicated a collective cellular behaviour and mechanical communication across scaffold pore walls. Surprisingly, the stiffness of the environment influenced cell behaviour even inside macroporous scaffolds where direct cell-cell contacts are hindered. Mechanical communication between cells via traction forces is essential for tissue adaptation to the environment and should not be blocked by rigid biomaterials. Copyright © 2017 John Wiley & Sons, Ltd.

Theory of Visual Attention (TVA) applied to mice in the 5-choice serial reaction time task

RATIONALE

The 5-choice serial reaction time task (5-CSRTT) is widely used to measure rodent attentional functions. In humans, many attention studies in healthy and clinical populations have used testing based on Bundesen's Theory of Visual Attention (TVA) to estimate visual processing speeds and other parameters of attentional capacity.

OBJECTIVES

We aimed to bridge these research fields by modifying the 5-CSRTT's design and by mathematically modelling data to derive attentional parameters analogous to human TVA-based measures.

METHODS

C57BL/6 mice were tested in two 1-h sessions on consecutive days with a version of the 5-CSRTT where stimulus duration (SD) probe length was varied based on information from previous TVA studies. Thereafter, a scopolamine hydrobromide (HBr; 0.125 or 0.25 mg/kg) pharmacological challenge was undertaken, using a Latin square design. Mean score values were modelled using a new three-parameter version of TVA to obtain estimates of visual processing speeds, visual thresholds and motor response baselines in each mouse.

RESULTS

The parameter estimates for each animal were reliable across sessions, showing that the data were stable enough to support analysis on an individual level. Scopolamine HBr dose-dependently reduced 5-CSRTT attentional performance while also increasing reward collection latency at the highest dose. Upon TVA modelling, scopolamine HBr significantly reduced visual processing speed at both doses, while having less pronounced effects on visual thresholds and motor response baselines.

CONCLUSIONS

This study shows for the first time how 5-CSRTT performance in mice can be mathematically modelled to yield estimates of attentional capacity that are directly comparable to estimates from human studies.

Endolymphatic Sac Tumor in Two Dogs

Endolymphatic sac tumors (ELSTs) are rare neoplasms of the inner and middle ear described in humans. Diagnosis of such neoplasms is difficult and largely dependent on a combination of histologic, immunohistochemical, and clinical findings. Although the neoplastic cells lack cellular features of malignancy, these are clinically aggressive tumors that often invade the surrounding temporal bone. Here, we describe 2 dogs with middle ear masses that share morphologic, immunohistochemical, and clinical similarities with human ELSTs. Advanced imaging of the masses revealed evidence of aggressive behavior such as bony lysis of the temporal bone. Histologically, the neoplastic epithelial cells formed papillary structures, lacked mitotic figures, and had mild anisocytosis and anisokaryosis. The neoplastic cells were immunohistochemically positive for cytokeratin AE1/AE3 but were negative for chromogranin, synaptophysin, and thyroglobulin. Local invasion and bone destruction but no evidence of metastases suggest a clinical behavior similar to human ELSTs.

Report of mecC-carrying MRSA in domestic swine

Objectives

We unexpectedly identified MRSA isolates carrying mecC (mecC-MRSA) from a Danish swine farm located in eastern Zealand. The objective of the present study was to investigate the origin of these isolates and their genetic relatedness to other mecC-MRSA isolates from Zealand.

Methods

WGS was used to infer the phylogenetic relationship between 19 identified mecC-MRSA isolates from the swine farm and 34 additional epidemiologically unrelated human isolates from the same geographical region of Denmark. Variations in the accessory genome were investigated by bioinformatics tools, and antibiotic susceptibility profiles were assessed by MIC determination.

Results

mecC-MRSA was isolated from a domestic swine farm, but not from cattle reared at the same farm. Phylogenetic analysis revealed that all mecC-MRSA isolates from both farm animals and workers formed a separate cluster, whereas human isolates from the same municipality belonged to a closely related cluster. Analysis of the accessory genome supported this relationship.

Conclusions

To the best of our knowledge, this is the first report of mecC-MRSA isolated from domestic swine. The investigation strongly indicates that transmission of mecC-MRSA has taken place on the swine farm between the farmers and swine. The close clustering of farm isolates and isolates from the same municipality suggests a local transmission of mecC-MRSA.

Long-term mortality and causes of death associated with Staphylococcus aureus bacteremia. A matched cohort study

OBJECTIVES

Data describing long-term mortality in patients with Staphylococcus aureus bacteremia (SAB) is scarce. This study investigated risk factors, causes of death and temporal trends in long-term mortality associated with SAB.

METHODS

Nationwide population-based matched cohort study. Mortality rates and ratios for 25,855 cases and 258,547 controls were analyzed by Poisson regression. Hazard ratio of death was computed by Cox proportional hazards regression analysis.

RESULTS

The majority of deaths occurred within the first year of SAB (44.6%) and a further 15% occurred within the following 2-5 years. The mortality rate was 14-fold higher in the first year after SAB and 4.5-fold higher overall for cases compared to controls. Increasing age, comorbidity and hospital contact within 90 days of SAB was associated with an increased risk of death. The overall relative risk of death decreased gradually by 38% from 1992-1995 to 2012-2014. Compared to controls, SAB patients were more likely to die from congenital malformation, musculoskeletal/skin disease, digestive system disease, genitourinary disease, infectious disease, endocrine disease, injury and cancer and less likely to die from respiratory disease, nervous system disease, unknown causes, psychiatric disorders, cardiovascular disease and senility. Over time, rates of death decreased or were stable for all disease categories except for musculoskeletal and skin disease where a trend towards an increase was seen.

CONCLUSION

Long-term mortality after SAB was high but decreased over time. SAB cases were more likely to die of eight specific causes of death and less likely to die of five other causes of death compared to controls. Causes of death decreased for most disease categories. Risk factors associated with long-term mortality were similar to those found for short-term mortality. To improve long-term survival after SAB, patients should be screened for comorbidity associated with SAB.

The relationship between expressive language level and psychological development in children with autism 5 years of age

The age of detection of autism varies and may be linked to differences in the severity of disturbance and any associated retardation. Symptom intensity, overall language level, age of recognition of first disturbances and level of psychological development were examined in 222 children with pervasive developmental disorder with a mean age of 5 years. Results showed a positive correlation between language level and psychological development as well as between language level and intensity of symptoms. The central position of language in psychological development is discussed.

Placental magnetic resonance imaging T2* measurements in normal pregnancies and in those complicated by fetal growth restriction

OBJECTIVES

The magnetic resonance imaging (MRI) variable transverse relaxation time (T2*) depends on multiple factors, one important one being the presence of deoxyhemoglobin. We aimed to describe placental T2* measurements in normal pregnancies and in those with fetal growth restriction (FGR).

METHODS

We included 24 normal pregnancies at 24-40 weeks' gestation and four FGR cases with an estimated fetal weight below the 1(st) centile. Prior to MRI, an ultrasound examination, including Doppler flow measurements, was performed. The T2* value was calculated using a gradient echo MRI sequence with readout at 16 different echo times. In normal pregnancies, repeat T2* measurements were performed and interobserver reproducibility was assessed in order to estimate the reproducibility of the method. Placental histological examination was performed in the FGR cases.

RESULTS

The method was robust regarding the technical and interobserver reproducibility. However, some slice-to-slice variation existed owing to the heterogeneous nature of the normal placenta. We therefore based T2* estimations on the average of two slices from each placenta. In normal pregnancies, the placental T2* value decreased significantly with increasing gestational age, with mean ± SD values of 120 ± 17 ms at 24 weeks' gestation, 84 ± 16 ms at 32 weeks and 47 ± 17 ms at 40 weeks. Three FGR cases had abnormal Doppler flow, histological signs of maternal hypoperfusion and a reduced T2* value (Z-score < -3.5). In the fourth FGR case, Doppler flow, placental histology and T2* value (Z-score, -0.34) were normal.

CONCLUSIONS

The established reference values for placental T2* may be clinically useful, as T2* values were significantly lower in FGR cases with histological signs of maternal hypoperfusion. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Pollen derived low molecular compounds enhance the human allergen specific immune response in vivo

BACKGROUND

Besides allergens, pollen release bioactive, low molecular weight compounds that modulate and stimulate allergic reactions. Clinical relevance of these substances has not been investigated to date.

OBJECTIVE

To elucidate the effect of a non-allergenic, low molecular weight factors from aqueous birch pollen extracts (Bet-APE < 3 kDa) on the human allergic immune response in vivo.

METHODS

Birch and grass pollen allergic individuals underwent skin prick testing with allergen alone, allergen plus Bet-APE < 3 kDa, or allergen plus pre-identified candidate substances from low molecular pollen fraction. Nasal allergen challenges were performed in non-atopic and pollen allergic individuals using a 3 day repeated threshold challenge battery. Subjects were either exposed to allergen alone or to allergen plus Bet-APE< 3 kDa. Local cytokine levels, nasal secretion weights, nasal congestion and symptom scores were determined.

RESULTS

Skin prick test reactions to pollen elicited larger weals when allergens were tested together with the low molecular weight compounds from pollen. Similar results were obtained with candidate pollen-associated lipid mediators. In nasal lining fluids of allergic patients challenged with allergen plus Bet-APE < 3 kDa, IL-8 and IgE was significantly increased as compared to allergen-only challenged patients. These patients also produced increased amounts of total nasal secretion and reported more severe rhinorrhea than the allergen-only challenged group.

CONCLUSIONS

Low molecular compounds from pollen enhance the allergen specific immune response in the skin and nose. They are therefore of potential clinical relevance in allergic patients.

Simple method for correct enumeration of Staphylococcus aureus

Optical density (OD) measurement is applied universally to estimate cell numbers of microorganisms growing in liquid cultures. It is a fast and reliable method but is based on the assumption that the bacteria grow as single cells of equal size and that the cells are dispersed evenly in the liquid culture. When grown in such liquid cultures, the human pathogen Staphylococcus aureus is characterized by its aggregation of single cells into clusters of variable size. Here, we show that aggregation during growth in the laboratory standard medium tryptic soy broth (TSB) is common among clinical and laboratory S. aureus isolates and that aggregation may introduce significant bias when applying standard enumeration methods on S. aureus growing in laboratory batch cultures. We provide a simple and efficient sonication procedure, which can be applied prior to optical density measurements to give an accurate estimate of cellular numbers in liquid cultures of S. aureus regardless of the aggregation level of the given strain. We further show that the sonication procedure is applicable for accurate determination of cell numbers using agar plate counting of aggregating strains.

Increased risk of arterial thromboembolic events after Staphylococcus aureus bacteremia: A matched cohort study

OBJECTIVES

An association between infection and arterial thromboembolic events (ATE) has been suggested. Here we examined the risk of myocardial infarction (MI), stroke and other ATE after Staphylococcus aureus bacteremia (SAB).

METHODS

Danish register-based nation-wide observational cohort study between 1995 and 2008 with matched control subjects from the general population.

RESULTS

Within a year, 278 of 15,669 SAB patients and 2570 of 156,690 controls developed MI, stroke or another ATE. The incidence rates among SAB patients were highest within the first 30 days and decreased over a year. The adjusted relative risk of MI, stroke and other ATE during the first 30 days after SAB in patients compared to controls were 2.2 (95% CI: 1.6-3.1), 5.5 (95% CI: 3.8-8.3) and 15.5 (95% CI: 6.9-35), respectively. Compared to controls, the increased adjusted relative risk persisted for 30 days for MI, 180 days for stroke and one year for other ATE. Increasing age, hypertension, atrial flutter/fibrillation, prior ATE and endocarditis in SAB patients were associated with an increased risk of ATE.

CONCLUSIONS

SAB was associated with a short-term increased risk of ATE that persisted longer dependent on type of event. Studies are warranted to investigate treatment strategies to diminish ATE after SAB.

Long-term persistence of a multi-resistant methicillin-susceptible Staphylococcus aureus (MR-MSSA) clone at a university hospital in southeast Sweden, without further transmission within the region

The objective of this study was to characterise isolates of methicillin-susceptible Staphylococcus aureus (MSSA) with resistance to clindamycin and/or tobramycin in southeast Sweden, including the previously described ECT-R clone (t002) found in Östergötland County, focusing on clonal relatedness, virulence determinants and existence of staphylococcal cassette chromosome (SCC) mec remnants. MSSA isolates with resistance to clindamycin and/or tobramycin were collected from the three county councils in southeast Sweden and investigated with spa typing, polymerase chain reaction (PCR) targeting the SCCmec right extremity junction (MREJ) and DNA microarray technology. The 98 isolates were divided into 40 spa types, and by microarray clustered in 17 multi-locus sequence typing (MLST) clonal complexes (MLST-CCs). All isolates with combined resistance to clindamycin and tobramycin (n = 12) from Östergötland County and two additional isolates (clindamycin-R) were designated as spa type t002, MREJ type ii and were clustered in CC5, together with a representative isolate of the ECT-R clone, indicating the clone's persistence. These isolates also carried several genes encoding exotoxins, Q9XB68-dcs and qacC. Of the isolates in CC15, 83% (25/30) were tobramycin-resistant and were designated spa type t084. Of these, 68% (17/25) were isolated from new-borns in all three counties. The persistence of the ECT-R clone in Östergötland County, although not found in any other county in the region, carrying certain virulence factors that possibly enhance its survival in the hospital environment, highlights the fact that basic hygiene guidelines must be maintained even when MRSA prevalence is low.

ECEL1 mutation causes fetal arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) is a descriptor for the clinical finding of congenital fixation of multiple joints. We present a consanguineous healthy couple with two pregnancies described with AMC due to characteristic findings on ultrasonography of fixated knee extension and reduced fetal movement at the gestational age of 13 weeks + 2 days and 12 weeks + 4 days. Both pregnancies were terminated and postmortem examinations were performed. The postmortem examinations confirmed AMC and suggested a diagnosis of centronuclear myopathy (CNM) due to characteristic histological findings in muscle biopsies. Whole exome sequencing (WES) was performed on all four individuals and the outcome was filtered by application of multiple filtration parameters satisfying a recessive inheritance pattern. Only one gene, ECEL1, was predicted damaging and had previously been associated with neuromuscular disease or AMC. The variant found ECEL1 is a missense mutation in a highly conserved residue and was predicted pathogenic by prediction software. The finding expands the molecular basis of congenital contractures and the phenotypic spectrum of ECEL1 mutations. The histological pattern suggestive of CNM in the fetuses can expand the spectrum of genes causing CNM, as we propose that mutations in ECEL1 can cause CNM or a condition similar to this. Further investigation of this is needed and we advocate that future patients with similar clinical presentation or proven ECEL1 mutations are examined with muscle biopsy. Secondly, this study illustrates the great potential of the clinical application of WES in couples with recurrent abortions or stillborn neonates.

Glioblastomas, astrocytomas and oligodendrogliomas linked to Lynch syndrome

BACKGROUND AND PURPOSE

Brain tumors represent a rare and relatively uncharacterized tumor type in Lynch syndrome.

METHODS

The national Danish Hereditary Nonpolyposis Colorectal Cancer Register was utilized to estimate the cumulative life-time risk for brain tumors in Lynch syndrome, and the mismatch repair (MMR) status in all tumors available was evaluated.

RESULTS

Primary brain tumors developed in 41/288 families at a median age of 41.5 (range 2-73) years. Biallelic MMR gene mutations were linked to brain tumor development in childhood. The risk of brain tumors was significantly higher (2.5%) in MSH2 gene mutation carriers compared to patients with mutations in MLH1 or MSH6. Glioblastomas predominated (56%), followed by astrocytomas (22%) and oligodendrogliomas (9%). MMR status was assessed in 10 tumors, eight of which showed MMR defects. None of these tumors showed immunohistochemical staining suggestive of the IDH1 R132H mutation.

CONCLUSION

In Lynch syndrome brain tumors occurred in 14% of the families with significantly higher risks for individuals with MSH2 gene mutations and development of childhood brain tumors in individuals with constitutional MMR defects.

Sleep and chronobiology in cluster headache

BACKGROUND AND AIM

Cluster headache (CH) is the headache disorder with the strongest chronobiological traits. The severe attacks of pain occur with diurnal and annual rhythmicity but the precise rhythm and involvement of potential zeitgebers is unknown. Patients complain of poor sleep quality yet this has never been studied. We investigated triggers, rhythms, sleep quality and chronotypes in CH.

METHODS

Patients and controls completed questionnaires and structured interviews composed of new and previously validated parts including the Pittsburgh Sleep Quality Index (PSQI) and Morningness-Eveningness Questionnaire (MEQ). Patients were characterized by a CH index, a unified measure of headache burden.

RESULTS

A total of 275 CH patients and 145 matched controls were included. The most common trigger was sleep (80%) and a relationship between clusters and daylight was identified. Of the patients, 82.2% reported diurnal and 56% annual rhythmicity. Patients reported impaired sleep quality (PSQI) (p < 0.0001) and an inverse relationship between time passed since last attack and sleep quality was identified (p < 0.0001). The CH index was positively related to the PSQI (p < 0.0001).

CONCLUSION

Diurnally, CH exhibits a relationship with night-time and annually with daylight hours. Patients' sleep quality is reduced compared with controls. Results suggest a complex relationship as sleep quality improves between clusters, but remains pathological.