Transplantation and Noninvasive Longitudinal In Vivo Imaging of Parathyroid Cells: A Proof-of-Concept Study

The parathyroid cell is a vital regulator of extracellular calcium levels, operating through the secretion of parathyroid hormone (PTH). Despite its importance, the regulation of PTH secretion remains complex and not fully understood, representing a unique interplay between extracellular and intracellular calcium, and hormone secretion. One significant challenge in parathyroid research has been the difficulty in maintaining cells ex vivo for in-depth cellular investigations. To address this issue, we introduce a novel platform for parathyroid cell transplantation and noninvasive in vivo imaging using the anterior chamber of the eye as a transplantation site. We found that parathyroid adenoma tissue transplanted into the mouse eye engrafted onto the iris, became vascularized, and retained cellular composition. Transplanted animals exhibited elevated PTH levels, indicating a functional graft. With in vivo confocal microscopy, we were able to repetitively monitor parathyroid graft morphology and vascularization. In summary, there is a pressing need for new methods to study complex cellular processes in parathyroid cells. Our study provides a novel approach for noninvasive in vivo investigations that can be applied to understand parathyroid physiology and pathology under physiological and pathological conditions. This innovative strategy can deepen our knowledge on parathyroid function and disease.

Olive oil consumption, plasma metabolites, and risk of type 2 diabetes and cardiovascular disease

BACKGROUND

Olive oil consumption has been inversely associated with the risk of type 2 diabetes (T2D) and cardiovascular disease (CVD). However, the impact of olive oil consumption on plasma metabolites remains poorly understood. This study aims to identify plasma metabolites related to total and specific types of olive oil consumption, and to assess the prospective associations of the identified multi-metabolite profiles with the risk of T2D and CVD.

METHODS

The discovery population included 1837 participants at high cardiovascular risk from the PREvención con DIeta MEDiterránea (PREDIMED) trial with available metabolomics data at baseline. Olive oil consumption was determined through food-frequency questionnaires (FFQ) and adjusted for total energy. A total of 1522 participants also had available metabolomics data at year 1 and were used as the internal validation sample. Plasma metabolomics analyses were performed using LC-MS. Cross-sectional associations between 385 known candidate metabolites and olive oil consumption were assessed using elastic net regression analysis. A 10-cross-validation (CV) procedure was used, and Pearson correlation coefficients were assessed between metabolite-weighted models and FFQ-derived olive oil consumption in each pair of training-validation data sets within the discovery sample. We further estimated the prospective associations of the identified plasma multi-metabolite profile with incident T2D and CVD using multivariable Cox regression models.

RESULTS

We identified a metabolomic signature for the consumption of total olive oil (with 74 metabolites), VOO (with 78 metabolites), and COO (with 17 metabolites), including several lipids, acylcarnitines, and amino acids. 10-CV Pearson correlation coefficients between total olive oil consumption derived from FFQs and the multi-metabolite profile were 0.40 (95% CI 0.37, 0.44) and 0.27 (95% CI 0.22, 0.31) for the discovery and validation sample, respectively. We identified several overlapping and distinct metabolites according to the type of olive oil consumed. The baseline metabolite profiles of total and extra virgin olive oil were inversely associated with CVD incidence (HR per 1SD: 0.79; 95% CI 0.67, 0.92 for total olive oil and 0.70; 0.59, 0.83 for extra virgin olive oil) after adjustment for confounders. However, no significant associations were observed between these metabolite profiles and T2D incidence.

CONCLUSIONS

This study reveals a panel of plasma metabolites linked to the consumption of total and specific types of olive oil. The metabolite profiles of total olive oil consumption and extra virgin olive oil were associated with a decreased risk of incident CVD in a high cardiovascular-risk Mediterranean population, though no associations were observed with T2D incidence.

TRIAL REGISTRATION

The PREDIMED trial was registered at ISRCTN ( http://www.isrctn.com/ , ISRCTN35739639).

Discovery of novel alkaline-tolerant xylanases from fecal microbiota of dairy cows

Xylo-oligosaccharides (XOS) are considered as a promising type of prebiotics that can be used in foods, feeds, and healthcare products. Xylanases play a key role in the production of XOS from xylan. In this study, we conducted a metagenomic analysis of the fecal microbiota from dairy cows fed with different types of fodders. Despite the diversity in their diets, the main phyla observed in all fecal microbiota were Firmicutes and Bacteroidetes. At the genus level, one group of dairy cows that were fed probiotic fermented herbal mixture-containing fodders displayed decreased abundance of Methanobrevibacter and increased growth of beneficial Akkermansia bacteria. Additionally, this group exhibited a high microbial richness and diversity. Through our analysis, we obtained a comprehensive dataset comprising over 280,000 carbohydrate-active enzyme genes. Among these, we identified a total of 163 potential xylanase genes and subsequently expressed 34 of them in Escherichia coli. Out of the 34 expressed genes, two alkaline xylanases with excellent temperature stability and pH tolerance were obtained. Notably, CDW-xyl-8 exhibited xylanase activity of 96.1 ± 7.5 U/mg protein, with an optimal working temperature of 55 ℃ and optimal pH of 8.0. CDW-xyl-16 displayed an activity of 427.3 ± 9.1 U/mg protein with an optimal pH of 8.5 and an optimal temperature at 40 ℃. Bioinformatic analyses and structural modeling suggest that CDW-xyl-8 belongs to GH10 family xylanase, and CDW-xyl-16 is a GH11 family xylanase. Both enzymes have the ability to hydrolyze beechwood xylan and produce XOS. In conclusion, this metagenomic study provides valuable insights into the fecal microbiota composition of dairy cows fed different fodder types, revealing main microbial groups and demonstrating the abundance of xylanases. Furthermore, the characterization of two novel xylanases highlights their potential application in XOS production.

Epidemiology and Causes of Primary Adrenal Insufficiency in Children: A Population-Based Study

CONTEXT

Incidence and causes of primary adrenal insufficiency (PAI) have not been comprehensively studied in children.

OBJECTIVE

Our objective was to describe the epidemiology and to assess causes of PAI in Finnish children.

METHODS

A population-based descriptive study of PAI in Finnish patients aged 0-20 years.Diagnoses referring to adrenal insufficiency in children born in 1996-2016 were collected from the Finnish National Care Register for Health Care. Patients with PAI were identified by studying patient records. Incidence rates were calculated in relation to person-years in the Finnish population of same age.

RESULTS

Of the 97 patients with PAI, 36% were female. The incidence of PAI was highest during the first year of life (in females 2.7 and in males 4.0/100 000 person-years). At 1-15 years of age, the incidence of PAI in females was 0.3/100 000 and in males 0.6/100 000 person-years. Cumulative incidence was 10/100 000 persons at age of 15 years and 13/100 000 at 20 years. Congenital adrenal hyperplasia was the cause in 57% of all patients and in 88% of patients diagnosed before age of 1 year. Other causes among the 97 patients included autoimmune disease (29%), adrenoleukodystrophy (6%), and other genetic causes (6%). From the age of 5 years, most of the new cases of PAI were due to autoimmune disease.

CONCLUSION

After the first-year peak, the incidence of PAI is relatively constant through ages 1-15 years, and 1 out of 10 000 children are diagnosed with PAI before the age of 15 years.

Generating Items for Measuring Needs-Based Quality of Life and Self-Perceived Health Inequity in Patients with Multimorbidity: Development of the MultiMorbidity Questionnaire (MMQ)

Purpose

To describe the processes of developing domains and items for the MultiMorbidity Questionnaire (MMQ), a multimorbidity-specific PROM for the assessment of Needs-based QoL.

Patients and Methods

We developed items and domains for the MMQ through 17 qualitative content validity questionnaire interviews with adults with multimorbidity by testing items from an item bank (covering items with content inspired by existing Needs-based QoL measures for single diseases). The interviews alternated between an explorative part and more focused cognitive interview techniques.

Results

Testing the 47 items from the first draft of the MMQ items showed that the Needs-based approach as a framework did not cover all the QoL aspects our informants stated as being important. Therefore, the conceptual framework was supplemented by Self-perceived health inequity, and new items were generated. MMQ, measuring Needs-based QoL (MMQ1) and Self-perceived health inequity (MMQ2), was assembled. MMQ1 covers the domains: "Physical ability" (10 items), "Limitations in everyday life" (15 items), "Worries" (11 items), "My social life" (11 items), "Self-image" (12 items), and "Personal finances" (2 items). Self-perceived health inequity proved to be a relevant framework for other aspects of QoL not covered by the Needs-based approach to QoL. MMQ2 covers the domains: "Experiences of being stigmatized" (five items), "Experiences of not being seen and heard" (four items), "Insufficient understanding of the burden of disease" (three items) and "Experiences of feeling powerless" (five items).

Conclusion

We have developed the final MMQ draft, a multimorbidity-specific PROM for the assessment of Needs-based QoL (MMQ1) and Self-perceived health inequity (MMQ2) with high content validity (regarding content relevance and comprehensiveness). The final MMQ draft will be assessed for its psychometric properties using Modern Test Theory.

Association between days alive without life support/out of hospital and health-related quality of life

BACKGROUND

Trials in critically ill patients increasingly focus on days alive without life support (DAWOLS) or days alive out of hospital (DAOOH) and health-related quality of life (HRQoL). DAWOLS and DAOOH convey more information than mortality and are simpler and faster to collect than HRQoL. However, whether these outcomes are associated with HRQoL is uncertain. We thus aimed to assess the associations between DAWOLS and DAOOH and long-term HRQoL.

METHODS

Secondary analysis of the COVID STEROID 2 trial including adults with COVID-19 and severe hypoxaemia and the Handling Oxygenation Targets in the Intensive Care Unit (HOT-ICU) trial including adult intensive care unit patients with acute hypoxaemic respiratory failure. Associations between DAWOLS and DAOOH at day 28 and 90 and long-term HRQoL (after 6 or 12 months) using the EuroQol 5-dimension 5-level survey (EQ VAS and EQ-5D-5L index values) were assessed using flexible models and evaluated using measures of fit and prediction adequacy in both datasets (comprising internal performance and external validation), non-parametric correlation coefficients and graphical presentations.

RESULTS

We found no strong associations between DAWOLS or DAOOH and HRQoL in survivors at HRQoL-follow-up (615 and 1476 patients, respectively). There was substantial variability in outcomes, and predictions from the best fitted models were poor both internally and externally in the other trial dataset, which also showed inadequate calibration. Moderate associations were found when including non-survivors, although predictions remained uncertain and calibration inadequate.

CONCLUSION

DAWOLS and DAOOH were poorly associated with HRQoL in adult survivors of severe or critical illness included in the COVID STEROID 2 and HOT-ICU trials.

Lower or higher oxygenation targets for acute Hypoxaemic respiratory failure: Protocol for an individual patient data meta-analysis

BACKGROUND

Supplemental oxygen therapy is central to the treatment of acute hypoxaemic respiratory failure, a condition which remains a major driver for morbidity and mortality in intensive care. Despite several large randomised clinical trials comparing a higher versus a lower oxygenation target for these patients, significant differences in study design impede analysis of aggregate data and final clinical recommendations.

METHODS

This paper presents the protocol for conducting an individual patient data meta-analysis where full individual patient data according to the intention-to-treat principle will be pooled from the HOT-ICU and HOT-COVID trials in a one-step procedure. The two trials are near-identical in design. We plan to use a hierarchical general linear mixed model that accounts for data clustering at a trial and site level. The primary outcome will be 90-day all-cause mortality while the secondary outcome will be days alive without life-support at 90 days. Further, we outline 14 clinically relevant predefined subgroups which we will analyse for heterogeneity in the intervention effects and interactions, and we present a plan for assessing the credibility of the subgroup analyses.

CONCLUSION

The presented individual patient data meta-analysis will synthesise individual level patient data from two of the largest randomised clinical trials on targeted oxygen therapy in intensive care. The results will provide a re-analysis of the intervention effects on the pooled intention-to-treat populations and facilitate subgroup analyses with an increased power to detect clinically important effect modifications.

Multimorbidity and determinants for initiating outpatient trajectories: A population-based study

INTRODUCTION

Individuals with multimorbidity often receive high numbers of hospital outpatient services in concurrent trajectories. Nevertheless, little is known about factors associated with initiating new hospital outpatient trajectories; identified as the continued use of outpatient contacts for the same medical condition.

PURPOSE

To investigate whether the number of chronic conditions and sociodemographic characteristics in adults with multimorbidity is associated with entering a hospital outpatient trajectory in this population.

METHODS

This population-based register study included all adults in Denmark with multimorbidity on January 1, 2018. The exposures were number of chronic conditions and sociodemographic characteristics, and the outcome was the rate of starting a new outpatient trajectory during 2018. Analyses were stratified by the number of existing outpatient trajectories. We used Poisson regression analysis, and results were expressed as incidence rates and incidence rate ratios with 95% confidence intervals. We followed the individuals during the entire year of 2018, accounting for person-time by hospitalization, emigration, and death.

RESULTS

Incidence rates for new outpatient trajectories were highest for individuals with low household income and ≥3 existing trajectories and for individuals with ≥3 chronic conditions and in no already established outpatient trajectory. A high number of chronic conditions and male gender were found to be determinants for initiating a new outpatient trajectory, regardless of the number of existing trajectories. Low educational level was a determinant when combined with 1, 2, and ≥3 existing trajectories, and increasing age, western ethnicity, and unemployment when combined with 0, 1, and 2 existing trajectories.

CONCLUSION

A high number of chronic conditions, male gender, high age, low educational level and unemployment were determinants for initiation of an outpatient trajectory. The rate was modified by the existing number of outpatient trajectories. The results may help identify those with multimorbidity at greatest risk of having a new hospital outpatient trajectory initiated.

Rheumatoid arthritis and the risk of postpartum psychiatric disorders: a Nordic population-based cohort study

BACKGROUND

Postpartum psychiatric disorders (PPD) are common complications of childbirth. A common explanation for their development is that the psychological, hormonal, and immune changes associated with pregnancy and parturition may trigger psychiatric symptoms postpartum. Rheumatoid arthritis (RA) is characterized by abnormalities in the activity of the hypothalamic-pituitary-adrenal axis and of the immune system, but its association with PPD is unknown. We analyzed whether women with RA before childbirth have an increased risk of PPD.

METHODS

We conducted a large population-based cohort study including mothers of singleton births in the Danish (1995-2015), Finnish (1997-2013), and Swedish Medical Birth Registers (2001-2013) (N = 3,516,849). We linked data from the Medical Birth Registers with data from several national socioeconomic and health registers. Exposure was defined as having a diagnosis of RA before childbirth, while the main outcome was a clinical diagnosis of psychiatric disorders 90 days postpartum. We analyzed the association between RA and PPD using Cox proportional hazard models, stratified by a personal history of psychiatric disorders.

RESULTS

Among women without a history of psychiatric disorders, the PPD incidence rate was 32.2 in the exposed and 19.5 per 1000 person-years in the unexposed group; women with RA had a higher risk of overall PPD than their unexposed counterparts [adjusted hazard ratio (HR) = 1.52, 95% confidence intervals (CI) 1.17 to 1.98]. Similar associations were also observed for postpartum depression (HR = 1.65, 95% CI 1.09 to 2.48) and other PPD (HR = 1.59, 95% CI 1.13 to 2.24). Among women with a history of psychiatric disorders, the incidence rate of overall PPD was 339.6 in the exposed and 346.6 per 1000 person-years in the unexposed group; RA was not associated with PPD. We observed similar associations between preclinical RA (RA diagnosed after childbirth) and PPD to those corresponding to clinical RA.

CONCLUSIONS

Rheumatoid arthritis was associated with an increased PPD risk in women without, but not in those with a psychiatric history. If our findings are confirmed in future studies, new mothers with RA may benefit from increased surveillance for new-onset psychiatric disorders postpartum.

Prevalence of Statin Use and Predictors of Statin Initiation Among Patients with Alcohol-Related Cirrhosis - A Danish Nationwide Cohort Study

Purpose

Statins reportedly increase the survival of patients with cirrhosis due to alcohol-related liver disease (ALD cirrhosis), but this association might be confounded by socioeconomic status. We examined the prevalence of statin use and socioeconomic and demographic predictors of statin initiation and discontinuation among patients with ALD cirrhosis.

Patients and Methods

Using Danish nationwide healthcare registries, we examined statin use among patients diagnosed with ALD cirrhosis in 1997-2018. We computed the prevalence of statin use and incidence of statin initiation and discontinuation, and we used multivariable Cox regression to identify predictors of statin initiation and discontinuation.

Results

We identified 28,260 patients with ALD cirrhosis in 1997-2018. During this period, the prevalence of statin use rose sharply, reaching 19.0% in late 2018. Among patients diagnosed with ALD cirrhosis after 2010, 16.9% were using statins when they were diagnosed with cirrhosis. Among the patients who did not use statins initially, those with lower educational attainment were more likely to begin taking them than those with higher attainment. Also, cohabiting patients were more likely to begin than patients who lived alone, and employed patients were more likely to begin compared to patients outside the labour force. Among current statin users, unemployment predicted statin discontinuation.

Conclusion

The use of statins has become increasingly prevalent among Danish patients with ALD cirrhosis, reaching 19.0% in 2018. Employment, cohabitation, and a short education predicted statin initiation after ALD cirrhosis diagnosis, and unemployment predicted statin discontinuation. Overall, statin use was not a marker of a high socioeconomic status.

Maternal Cigarette Smoking During Pregnancy and Genital Anomalies in Boys: A Register-Based Cohort and Sibling-Matched Design Study

Purpose

Cryptorchidism and hypospadias share several prenatal risk factors. However, in published studies, boys exposed to cigarette smoking during pregnancy have a higher risk of cryptorchidism and a lower risk of hypospadias. Using Danish register-based data, we revisited these findings with a cohort and sibling-matched design to investigate the potential effect of shared time-stable factors.

Patients and Methods

For the cohort study, we included 823,670 live-born, singleton boys born from 1991 to 2016. Crude and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox regression models for each genital anomaly according to maternal cigarette smoking during pregnancy. For the sibling-matched design, we included 399,258 brothers and used a stratified Cox regression model creating family-adjusted results.

Results

In the cohort study, we found a higher risk of cryptorchidism (aHR = 1.18, 95% CI: 1.12, 1.24) and a lower risk of hypospadias (aHR = 0.84, 95% CI: 0.76, 0.93) when comparing boys exposed to cigarette smoking with non-exposed, and for increasing numbers of cigarettes smoked. In comparison, the sibling-matched analyses suggested a slightly weaker association for cryptorchidism and an association of similar magnitude for hypospadias, both in the same direction as in the cohort study.

Conclusion

Shared, familial confounding does not seem to explain earlier findings of higher risk of cryptorchidism and lower risk of hypospadias.

Association between prenatal exposure to perfluoroalkyl substances and asthma in 5-year-old children in the Odense Child Cohort

BACKGROUND

Asthma is the most common non-communicable disease in children. Prenatal exposure to perfluoroalkyl substances (PFASs), a group of persistent environmental chemicals with endocrine disrupting abilities, has been associated with immunomodulation and may contribute to the aetiology of asthma. We investigated the associations between prenatal exposure to five PFASs and asthma in 5-year-old children.

METHODS

We studied 981 mother-child pairs within the Odense Child Cohort (OCC), Denmark. We measured perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) in maternal serum donated in early pregnancy. A standardized questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC) was used to assess wheeze, self-reported asthma and doctor-diagnosed asthma among children at age 5 years. Associations were examined using logistic regression analyses adjusting for parity, maternal educational level, maternal pre-pregnancy BMI, asthma predisposition and child sex.

RESULTS

Among the 5-year-old children 18.6% reported wheeze and 7.1% reported asthma. We found no association between prenatal exposure to PFAS and doctor-diagnosed asthma or wheeze. Prenatal PFAS exposure was associated with self-reported asthma, although only significant for PFNA (OR = 1.84, 95% CI 1.03,3.23).

CONCLUSION

Our findings support the suggested immunomodulatory effects of PFASs, however, additional studies are warranted. In order to verify our findings, it is important to re-examine the children with postnatal measurements of serum PFAS concentrations and additional clinical diagnostic testing at an older age where an asthma diagnosis is more valid.

Mining, analyzing, and integrating viral signals from metagenomic data

BACKGROUND

Viruses are important components of microbial communities modulating community structure and function; however, only a couple of tools are currently available for phage identification and analysis from metagenomic sequencing data. Here we employed the random forest algorithm to develop VirMiner, a web-based phage contig prediction tool especially sensitive for high-abundances phage contigs, trained and validated by paired metagenomic and phagenomic sequencing data from the human gut flora.

RESULTS

VirMiner achieved 41.06% ± 17.51% sensitivity and 81.91% ± 4.04% specificity in the prediction of phage contigs. In particular, for the high-abundance phage contigs, VirMiner outperformed other tools (VirFinder and VirSorter) with much higher sensitivity (65.23% ± 16.94%) than VirFinder (34.63% ± 17.96%) and VirSorter (18.75% ± 15.23%) at almost the same specificity. Moreover, VirMiner provides the most comprehensive phage analysis pipeline which is comprised of metagenomic raw reads processing, functional annotation, phage contig identification, and phage-host relationship prediction (CRISPR-spacer recognition) and supports two-group comparison when the input (metagenomic sequence data) includes different conditions (e.g., case and control). Application of VirMiner to an independent cohort of human gut metagenomes obtained from individuals treated with antibiotics revealed that 122 KEGG orthology and 118 Pfam groups had significantly differential abundance in the pre-treatment samples compared to samples at the end of antibiotic administration, including clustered regularly interspaced short palindromic repeats (CRISPR), multidrug resistance, and protein transport. The VirMiner webserver is available at http://sbb.hku.hk/VirMiner/ .

CONCLUSIONS

We developed a comprehensive tool for phage prediction and analysis for metagenomic samples. Compared to VirSorter and VirFinder-the most widely used tools-VirMiner is able to capture more high-abundance phage contigs which could play key roles in infecting bacteria and modulating microbial community dynamics.

TRIAL REGISTRATION

The European Union Clinical Trials Register, EudraCT Number: 2013-003378-28 . Registered on 9 April 2014.

Abnormal islet sphingolipid metabolism in type 1 diabetes

AIMS/HYPOTHESIS

Sphingolipids play important roles in beta cell physiology, by regulating proinsulin folding and insulin secretion and in controlling apoptosis, as studied in animal models and cell cultures. Here we investigate whether sphingolipid metabolism may contribute to the pathogenesis of human type 1 diabetes and whether increasing the levels of the sphingolipid sulfatide would prevent models of diabetes in NOD mice.

METHODS

We examined the amount and distribution of sulfatide in human pancreatic islets by immunohistochemistry, immunofluorescence and electron microscopy. Transcriptional analysis was used to evaluate expression of sphingolipid-related genes in isolated human islets. Genome-wide association studies (GWAS) and a T cell proliferation assay were used to identify type 1 diabetes related polymorphisms and test how these affect cellular islet autoimmunity. Finally, we treated NOD mice with fenofibrate, a known activator of sulfatide biosynthesis, to evaluate the effect on experimental autoimmune diabetes development.

RESULTS

We found reduced amounts of sulfatide, 23% of the levels in control participants, in pancreatic islets of individuals with newly diagnosed type 1 diabetes, which were associated with reduced expression of enzymes involved in sphingolipid metabolism. Next, we discovered eight gene polymorphisms (ORMDL3, SPHK2, B4GALNT1, SLC1A5, GALC, PPARD, PPARG and B4GALT1) involved in sphingolipid metabolism that contribute to the genetic predisposition to type 1 diabetes. These gene polymorphisms correlated with the degree of cellular islet autoimmunity in a cohort of individuals with type 1 diabetes. Finally, using fenofibrate, which activates sulfatide biosynthesis, we completely prevented diabetes in NOD mice and even reversed the disease in half of otherwise diabetic animals.

CONCLUSIONS/INTERPRETATION

These results indicate that islet sphingolipid metabolism is abnormal in type 1 diabetes and suggest that modulation may represent a novel therapeutic approach.

DATA AVAILABILITY

The RNA expression data is available online at https://www.dropbox.com/s/93mk5tzl5fdyo6b/Abnormal%20islet%20sphingolipid%20metabolism%20in%20type%201%20diabetes%2C%20RNA%20expression.xlsx?dl=0 . A list of SNPs identified is available at https://www.dropbox.com/s/yfojma9xanpp2ju/Abnormal%20islet%20sphingolipid%20metabolism%20in%20type%201%20diabetes%20SNP.xlsx?dl=0 .

Aberrant intestinal microbiota in individuals with prediabetes

AIMS/HYPOTHESIS

Individuals with type 2 diabetes have aberrant intestinal microbiota. However, recent studies suggest that metformin alters the composition and functional potential of gut microbiota, thereby interfering with the diabetes-related microbial signatures. We tested whether specific gut microbiota profiles are associated with prediabetes (defined as fasting plasma glucose of 6.1-7.0 mmol/l or HbA_1c of 42-48 mmol/mol [6.0-6.5%]) and a range of clinical biomarkers of poor metabolic health.

METHODS

In the present case-control study, we analysed the gut microbiota of 134 Danish adults with prediabetes, overweight, insulin resistance, dyslipidaemia and low-grade inflammation and 134 age- and sex-matched individuals with normal glucose regulation.

RESULTS

We found that five bacterial genera and 36 operational taxonomic units (OTUs) were differentially abundant between individuals with prediabetes and those with normal glucose regulation. At the genus level, the abundance of Clostridium was decreased (mean log₂ fold change -0.64 (SEM 0.23), p _adj  = 0.0497), whereas the abundances of Dorea, [Ruminococcus], Sutterella and Streptococcus were increased (mean log₂ fold change 0.51 (SEM 0.12), p _adj  = 5 × 10^-4; 0.51 (SEM 0.11), p _adj  = 1 × 10^-4; 0.60 (SEM 0.21), p _adj  = 0.0497; and 0.92 (SEM 0.21), p _adj  = 4 × 10^-4, respectively). The two OTUs that differed the most were a member of the order Clostridiales (OTU 146564) and Akkermansia muciniphila, which both displayed lower abundance among individuals with prediabetes (mean log₂ fold change -1.74 (SEM 0.41), p _adj  = 2 × 10^-3 and -1.65 (SEM 0.34), p _adj  = 4 × 10^-4, respectively). Faecal transfer from donors with prediabetes or screen-detected, drug-naive type 2 diabetes to germfree Swiss Webster or conventional C57BL/6 J mice did not induce impaired glucose regulation in recipient mice.

CONCLUSIONS/INTERPRETATION

Collectively, our data show that individuals with prediabetes have aberrant intestinal microbiota characterised by a decreased abundance of the genus Clostridium and the mucin-degrading bacterium A. muciniphila. Our findings are comparable to observations in overt chronic diseases characterised by low-grade inflammation.

DNA replication stress mediates APOBEC3 family mutagenesis in breast cancer

BACKGROUND

The APOBEC3 family of cytidine deaminases mutate the cancer genome in a range of cancer types. Although many studies have documented the downstream effects of APOBEC3 activity through next-generation sequencing, less is known about their upstream regulation. In this study, we sought to identify a molecular basis for APOBEC3 expression and activation.

RESULTS

HER2 amplification and PTEN loss promote DNA replication stress and APOBEC3B activity in vitro and correlate with APOBEC3 mutagenesis in vivo. HER2-enriched breast carcinomas display evidence of elevated levels of replication stress-associated DNA damage in vivo. Chemical and cytotoxic induction of replication stress, through aphidicolin, gemcitabine, camptothecin or hydroxyurea exposure, activates transcription of APOBEC3B via an ATR/Chk1-dependent pathway in vitro. APOBEC3B activation can be attenuated through repression of oncogenic signalling, small molecule inhibition of receptor tyrosine kinase signalling and alleviation of replication stress through nucleoside supplementation.

CONCLUSION

These data link oncogene, loss of tumour suppressor gene and drug-induced replication stress with APOBEC3B activity, providing new insights into how cytidine deaminase-induced mutagenesis might be activated in tumourigenesis and limited therapeutically.

Diurnal Cortisol Patterns and Dexamethasone Suppression Test Responses in Healthy Young Adults Born Preterm at Very Low Birth Weight

Background

Early life stress, such as painful and stressful procedures during neonatal intensive care after preterm birth, can permanently affect physiological, hormonal and neurobiological systems. This may contribute to altered programming of the hypothalamic-pituitary-adrenal axis (HPAA) and provoke changes in HPAA function with long-term health impacts. Previous studies suggest a lower HPAA response to stress in young adults born preterm compared with controls born at term. We assessed whether these differences in HPAA stress responsiveness are reflected in everyday life HPAA functioning, i.e. in diurnal salivary cortisol patterns, and reactivity to a low-dose dexamethasone suppression test (DST), in unimpaired young adults born preterm at very low birth weight (VLBW; <1500 g).

Methods

The participants were recruited from the Helsinki Study of Very Low Birth Weight Adults cohort study. At mean age 23.3 years (2.1 SD), 49 VLBW and 36 controls born at term participated in the study. For cortisol analyzes, saliva samples were collected on two consecutive days at 0, 15, 30 and 60 min after wake-up, at 12:00 h, 17:00 h and 22:00 h. After the last salivary sample of the first study day the participants were instructed to take a 0.5 mg dexamethasone tablet.

Results

With mixed-effects model no difference was seen in overall diurnal salivary cortisol between VLBW and control groups [13.9% (95% CI: -11.6, 47.0), P = 0.31]. Salivary cortisol increased similarly after awakening in both VLBW and control participants [mean difference -2.9% (29.2, 33.0), P = 0.85]. Also reactivity to the low-dose DST (awakening cortisol ratio day2/day1) was similar between VLBW and control groups [-1.1% (-53.5, 103.8), P = 0.97)].

Conclusions

Diurnal cortisol patterns and reactivity to a low-dose DST in young adulthood were not associated with preterm birth.