Longitudinal associations of plasma kynurenines and ratios with anxiety and depression scores in colorectal cancer survivors up to 12 months post-treatment

INTRODUCTION

Colorectal cancer (CRC) survivors often experience neuropsychological symptoms, including anxiety and depression. Mounting evidence suggests a role for the kynurenine pathway in these symptoms due to potential neuroprotective and neurotoxic roles of involved metabolites. However, evidence remains inconclusive and insufficient in cancer survivors. Thus, we aimed to explore longitudinal associations of plasma tryptophan, kynurenines, and their established ratios with anxiety and depression in CRC survivors up to 12 months post-treatment.

METHODS

In 249 stage I-III CRC survivors, blood samples were collected at 6 weeks, 6 months, and 12 months post-treatment to analyze plasma concentrations of tryptophan and kynurenines using liquid-chromatography tandem-mass spectrometry (LC/MS-MS). At the same timepoints, anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS). Confounder-adjusted linear mixed models were used to analyze longitudinal associations. Sensitivity analyses with false discovery rate (FDR) correction were conducted to adjust for multiple testing.

RESULTS

Higher plasma tryptophan concentrations were associated with lower depression scores (β as change in depression score per 1 SD increase in the ln-transformed kynurenine concentration: -0.31; 95%CI: -0.56,-0.05), and higher plasma 3-hydroxyanthranilic acid concentrations with lower anxiety scores (-0.26; -0.52,-0.01). A higher 3-hydroxykynurenine ratio (HKr; the ratio of 3-hydroxykynurenine to the sum of kynurenic acid, xanthurenic acid, anthranilic acid, and 3-hydroxyanthranilic acid) was associated with higher depression scores (0.34; 0.04,0.63) and higher total anxiety and depression scores (0.53; 0.02,1.04). Overall associations appeared to be mainly driven by inter-individual associations, which were statistically significant for tryptophan with depression (-0.60; -1.12,-0.09), xanthurenic acid with total anxiety and depression (-1.04; -1.99,-0.10), anxiety (-0.51; -1.01,-0.01), and depression (-0.56; -1.08,-0.05), and kynurenic-acid-to-quinolinic-acid ratio with depression (-0.47; -0.93,-0.01). In sensitivity analyses, associations did not remain statistically significant after FDR adjustment.

CONCLUSION

We observed that plasma concentrations of tryptophan, 3-hydroxyanthranilic acid, xanthurenic acid, 3-hydroxykynurenine ratio, and kynurenic-acid-to-quinolinic-acid ratio tended to be longitudinally associated with anxiety and depression in CRC survivors up to 12 months post-treatment. Future studies are warranted to further elucidate the association of plasma kynurenines with anxiety and depression.

Inflammation, the kynurenines, and mucosal injury during human experimental enterotoxigenic Escherichia coli infection

Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea in children and travelers, especially in low- and middle-income countries. ETEC is a non-invasive gut pathogen colonizing the small intestinal wall before secreting diarrhea-inducing enterotoxins. We sought to investigate the impact of ETEC infection on local and systemic host defenses by examining plasma markers of inflammation and mucosal injury as well as kynurenine pathway metabolites. Plasma samples from 21 volunteers experimentally infected with ETEC were collected before and 1, 2, 3, and 7 days after ingesting the ETEC dose, and grouped based on the level of intestinal ETEC proliferation: 14 volunteers experienced substantial proliferation (SP) and 7 had low proliferation (LP). Plasma markers of inflammation, kynurenine pathway metabolites, and related cofactors (vitamins B2 and B6) were quantified using targeted mass spectrometry, whereas ELISA was used to quantify the mucosal injury markers, regenerating islet-derived protein 3A (Reg3a), and intestinal fatty acid-binding protein 2 (iFABP). We observed increased concentrations of plasma C-reactive protein (CRP), serum amyloid A (SAA), neopterin, kynurenine/tryptophan ratio (KTR), and Reg3a in the SP group following dose ingestion. Vitamin B6 forms, pyridoxal 5'-phosphate and pyridoxal, decreased over time in the SP group. CRP, SAA, and pyridoxic acid ratio correlated with ETEC proliferation levels. The changes following experimental ETEC infection indicate that ETEC, despite causing a non-invasive infection, induces systemic inflammation and mucosal injury when proliferating substantially, even in cases without diarrhea. It is conceivable that ETEC infections, especially when repeated, contribute to negative health impacts on children in ETEC endemic areas.

Preoperative risk factors associated with left ventricular dysfunction after bariatric surgery

A large proportion of patients with severe obesity remain with left ventricular (LV) dysfunction after bariatric surgery. We assessed whether preoperative evaluation by echocardiography and inflammatory proteins can identify this high-risk group. In the Bariatric Surgery on the West Coast of Norway study, 75 patients (44 ± 10 years, body mass index [BMI] 41.5 ± 4.7 kg/m2) were prospectively evaluated by echocardiography and inflammatory proteins (high-sensitivity C-reactive protein [hsCRP], serum amyloid A [SAA] and calprotectin) before and one year after Roux-en-Y gastric bypass surgery. LV mechanics was assessed by the midwall shortening (MWS) and global longitudinal strain (GLS). Bariatric surgery improved BMI and GLS, and lowered hsCRP, calprotectin and SAA (p < 0.05). MWS remained unchanged and 35% of patients had impaired MWS at 1-year follow-up. A preoperative risk index including sex, hypertension, ejection fraction (EF) and high hsCRP (index 1) or SAA (index 2) predicted low 1-year MWS with 81% sensitivity/71% specificity (index 1), and 77% sensitivity/77% specificity (index 2) in ROC analyses (AUC 0.80 and 0.79, p < 0.001). Among individuals with severe obesity, women and patients with hypertension, increased serum levels of inflammatory proteins and reduced EF are at high risk of impaired LV midwall mechanics 1 year after bariatric surgery.ClinicalTrials.gov identifier NCT01533142 February 15, 2012.

The inverse association between the apolipoprotein E ε4 allele and C-reactive protein levels is stronger in persons with obesity and diabetes

BACKGROUND

C-reactive protein (CRP) is lower in patients who carry the apolipoprotein E epsilon 4 allele variant (APOEε4) of the APOE gene. This could however be explained by other factors observed in APOEε4 carriers, such as lower body mass index (BMI), possibly less diabetes and more use of statins, all associated with CRP concentrations.

OBJECTIVES

To assess the association between CRP and APOEε4 stratified by BMI, statin use and diabetes.

METHODS

We included 2700 community-dwelling older adults from the Hordaland health study with genotyping of the APOE gene by a one-step polymerase chain reaction and CRP measured using immuno-MALDI-TOF MS. Differences in CRP concentrations by APOE (ε4 vs no ε4) were assessed using the Mann-Whitney U tests, also stratified by statin use, diabetes and BMI categories. Finally, we performed linear regression with log (CRP) as the outcome and APOEε4 together with statin use, diabetes, BMI and their respective interactions.

RESULTS

CRP was higher in APOEε4 carriers irrespective of BMI, diabetes and statin use. In APOEε4 non-carriers, CRP was elevated with diabetes and obesity as expected. However, this was attenuated or even reversed in APOEε4 carriers. Such differences were not observed for statin use.

CONCLUSIONS

Statin use, obesity or diabetes did not confound the known association between the APOEε4 allele and lower CRP. Our data suggest that CRP is less responsive to inflammatory cues involved in diabetes and obesity in APOEε4 carriers. Epidemiological studies should take note of these relationships, as CRP, APOEε4, diabetes and obesity are both linked to neurodegenerative and cardiovascular disease.

Cystatin C proteoforms in chronic kidney disease

Cystatin C, a cysteine protease inhibitor, is used as a biomarker of renal function. It offers several advantages compared to creatinine, and formulas for the estimation of the glomerular filtration rate based on cystatin C have been developed. Recently, several proteoforms of cystatin C have been discovered, including an intact protein with a hydroxylated proline at the N-terminus, and N-terminal truncated forms. There is little knowledge about the biological significance of these proteoforms.

METHODS

Cross-sectional study of patients with different stages of chronic renal disease (pre-dialysis n = 53; hemodialysis n = 51, renal transplant n = 53). Measurement of cystatin C proteoforms by MALDI-TOF MS, assessment of medicine prescription using the first two levels of the Anatomical Therapeutic chemical system from patients' records.

RESULTS

Patients receiving hemodialysis had the highest cystatin C concentrations, followed by pre-dialysis patients and patients with a renal transplant. In all groups, the most common proteoforms were native cystatin C and CysC 3Pro-OH while the truncated forms made up 28%. The distribution of the different proteoforms was largely independent of renal function and total cystatin C. However, the use of corticosteroids (ATC-L02) and immunosuppressants (ATC-H04) considerably impacted the distribution of proteoforms.

CONCLUSION

The different proteoforms of cystatin C increased proportionally with total cystatin C in patients with chronic kidney disease. Prescription of corticosteroids and immunosuppressants had a significant effect on the distribution of proteoforms. The biological significance of these proteoforms remains to be determined.

A cross-sectional study of inflammatory markers as determinants of circulating kynurenines in the Lung Cancer Cohort Consortium

Circulating concentrations of metabolites (collectively called kynurenines) in the kynurenine pathway of tryptophan metabolism increase during inflammation, particularly in response to interferon-gamma (IFN-γ). Neopterin and the kynurenine/tryptophan ratio (KTR) are IFN-γ induced inflammatory markers, and together with C-reactive protein (CRP) and kynurenines they are associated with various diseases, but comprehensive data on the strength of associations of inflammatory markers with circulating concentrations of kynurenines are lacking. We measured circulating concentrations of neopterin, CRP, tryptophan and seven kynurenines in 5314 controls from 20 cohorts in the Lung Cancer Cohort Consortium (LC3). The associations of neopterin, KTR and CRP with kynurenines were investigated using regression models. In mixed models, one standard deviation (SD) higher KTR was associated with a 0.46 SD higher quinolinic acid (QA), and 0.31 SD higher 3-hydroxykynurenine (HK). One SD higher neopterin was associated with 0.48, 0.44, 0.36 and 0.28 SD higher KTR, QA, kynurenine and HK, respectively. KTR and neopterin respectively explained 24.1% and 16.7% of the variation in QA, and 11.4% and 7.5% of HK. CRP was only weakly associated with kynurenines in regression models. In summary, QA was the metabolite that was most strongly associated with the inflammatory markers. In general, the inflammatory markers were most strongly related to metabolites located along the tryptophan-NAD axis, which may support suggestions of increased production of NAD from tryptophan during inflammation.

Glycated haemoglobin and the association with long-term survival among patients evaluated for stable angina – a prospective Norwegian cohort

Background and methods

Recent guidelines have included glycated haemoglobin (HbA1c) ≥48 mmol/L as a diagnostic criterion for diabetes mellitus (DM) in addition to plasma glucose (PG) concentrations, mainly based on the relationship between hyperglycemia and microvascular disease [1]. However, increased HbA1c may stem not only from hyperglycemia, and the risk association between HbA1c and long-term survival in patients with stable coronary heart disease and HbA1c ≥48 mmol/L but no previous DM according to PG is uncertain. We explored the relationship between HbA1c and survival among patients with and without DM who were evaluated for stable angina in the period 2000–2004. Endpoints were obtained from the Norwegian Cause of Death Registry.

Results

In total, 4164 patients were evaluated by cardiac cathetherization, of whom 576 patients (13.8%) had DM (median HbA1c 55 mmol/L) according to self-report and/or baseline PG concentrations. Of the remaining 3588 patients 1026 had HbA1c ≥48 mmol/L; however, HbA1c did not correlate with the HOMA2 insulin resistance index or fasting PG in these patients. During median (25–75 percentile) follow-up time of 14.0 (12.1–15.4) years a total of 1328 patients (31.9%) died, of whom 582 from cardiovascular causes. In patients with DM according to PG, HbA1c trended towards positive associations with all-cause and CVD mortality when adjusted for age and gender (HRs (95% CIs) 1.13 (0.99–1.28) and 1.16 (0.98–1.39) per 1SD, respectively). However, HbA1c was not associated with survival in either the group of patients without DM and HbA1c &lt;48 mmol/L (median HbA1c 38 mmol/L) (HRs (95% CIs) 0.99 (0.92–1.06) and 0.96 (0.86–1.08) for all-cause and CVD mortality, respectively) or patients without DM but having HbA1c ≥48 mmol/L (median HbA1c 53 mmol/L) (HRs (95% CIs) 0.99 (0.88–1.12) and 1.04 (0.88–1.22)).

Conclusion

In patients evaluated for stable angina pectoris about two decades ago, almost a third of patients with no history of DM according to PG still had HbA1c concentrations indicating DM according to current guidelines. Including these patients in the DM category yielded similar percentages of patients with DM as observed in recent populations with stable coronary disease [2]. However, as opposed to what we observed in patients with DM, HbA1c did not show any association with very long-term survival among patients without DM. Our findings therefore question the use of HbA1c in the diagnosis of DM, especially in terms of risk assessment for longevity among patients with chronic coronary syndrome.

Funding Acknowledgement

Type of funding sources: None.

Inflammation and cardiorespiratory fitness in overweight women and men: the FATCOR study

Background

Women have more body fat compared to men, and adipose tissue is associated with chronic inflammation. Cardiorespiratory fitness has on the other hand been postulated to lower chronic inflammation. However, sex-specific associations of inflammation with cardiorespiratory fitness is less studied.

Purpose

To assess inflammatory markers in overweight and obese women and men according to cardiorespiratory fitness in the FAT associated CardiOvasculaR dysfunction (FATCOR) study.

Methods

Cardiorespiratory fitness was assessed by maximal oxygen uptake (VO2max) by cardiopulmonary exercise testing in 566 subjects (mean age was 48±9 years, 60% women) with body mass index (BMI) &gt;27.0 kg/m2. Participants were grouped according to sex, and fitness status identified from sex and age specific VO2max thresholds. C-reactive protein (CRP) and serum amyloid A (SAA) were analysed using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight mass spectrometry. Serum levels of the kynurenine:tryptophan ratio (KTR) and pyriodoxic acid ratio (PAr) were measured by liquid chromatography tandem mass spectrometry. All inflammatory markers were log transformed before inclusion in linear regression analyses.

Results

In the total study population, 63% had obesity and 74% were cardiorespiratory unfit. Unfit women had the highest fat percentage and the highest serum levels of CRP and SAA compared to the other groups (p&lt;0.05), while serum levels of KTR and PAr were higher only compared to fit men (p&lt;0.05). In multivariable linear regression analyses in women, higher CRP (β −0.15, p=0.001), SAA (β −0.10, p=0.03) and PAr (β −0.09, p=0.03) were associated with lower VO2max after adjusting for age, fat percentage, hypertension and metabolic syndrome. In men, only higher PAr (β −0.14, p=0.02) was associated with lower VO2max in multivariable analyses adjusted for age, fat percentage and metabolic syndrome. In multivariable analyses in obese women only (n=213), higher CRP (β −0.15, p=0.01) and PAr (β −0.13, p=0.03) remained associated with lower VO2max, while in obese men (n=144) there was no significant associations between inflammatory markers and VO2max.

Conclusion

Among overweight subjects participating in the FATCOR study, cardiorespiratory unfit women had the highest serum levels of inflammatory markers. The association of inflammation with reduced cardiorespiratory fitness was more pronounced in women than men, in particular when obesity was present.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Western Regional Health Authority of Norway

Association of Markers of Inflammation, the Kynurenine Pathway and B Vitamins with Age and Mortality, and a Signature of Inflammaging

BACKGROUND

Inflammation is a key feature of aging. We aimed to (i) investigate the association of 34 blood markers potentially involved in inflammatory processes with age and mortality and (ii) develop a signature of "inflammaging."

METHODS

Thirty-four blood markers relating to inflammation, B vitamin status, and the kynurenine pathway were measured in 976 participants in the Melbourne Collaborative Cohort Study at baseline (median age = 59 years) and follow-up (median age = 70 years). Associations with age and mortality were assessed using linear and Cox regression, respectively. A parsimonious signature of inflammaging was developed and its association with mortality was compared with 2 marker scores calculated across all markers associated with age and mortality, respectively.

RESULTS

The majority of markers (30/34) were associated with age, with stronger associations observed for neopterin, cystatin C, interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), several markers of the kynurenine pathway and derived indices KTR (kynurenine/tryptophan ratio), PAr index (ratio of 4-pyridoxic acid and the sum of pyridoxal 5'-phosphate and pyridoxal), and HK:XA (3-hydroxykynurenine/xanthurenic acid ratio). Many markers (17/34) showed an association with mortality, in particular IL-6, neopterin, C-reactive protein, quinolinic acid, PAr index, and KTR. The inflammaging signature included 10 markers and was strongly associated with mortality (hazard ratio [HR] per SD = 1.40, 95% CI: 1.24-1.57, p = 2 × 10-8), similar to scores based on all age-associated (HR = 1.38, 95% CI: 1.23-1.55, p = 4 × 10-8) and mortality-associated markers (HR = 1.43, 95% CI: 1.28-1.60, p = 1 × 10-10), respectively. Strong evidence of replication of the inflammaging signature association with mortality was found in the Hordaland Health Study.

CONCLUSION

Our study highlights the key role of the kynurenine pathway and vitamin B6 catabolism in aging, along with other well-established inflammation-related markers. A signature of inflammaging based on 10 markers was strongly associated with mortality.

Biomarkers of inflammation and left ventricular remodelling in psoriasis patients treated with infliximab

Objective: Psoriasis is an immune mediated disorder associated with T cell activation and cardiovascular disease (CVD). We explored the association of inflammation with left ventricular (LV) remodelling in psoriasis patients receiving treatment with the tumour necrosis factor-α (TNF-α) blocker infliximab. Methods: Psoriasis patients (n = 47, age 47 ± 14 years, 66% men) and 99 control subjects without psoriasis (age 47 ± 11 years, 72% men) were examined by echocardiography in a cross-sectional study. LV remodelling was assessed by LV mass index for height in the allometric power of 2.7. Serum concentrations of C-reactive protein (CRP), serum amyloid A (SAA), neopterin, kynurenine:tryptophan ratio (KTR) and the pyridoxic acid ratio (PAr) index were measured. Results: Serum concentration of neopterin (p = .007) was higher in psoriasis patients, while the other inflammatory biomarkers had similar levels. LV mass index was lower in patients than controls (35.6 ± 9.6 g/m^2.7 vs. 40.3 ± 9.8 g/m^2.7, p = .008). In the total study population, serum SAA (β = 0.18, p = .02), KTR (β = 0.20, p = .02) and the PAr index (β = 0.26, p = .002) were all associated with higher LV mass index independent of age, sex, body mass index, hypertension, smoking, renal function and psoriasis. Also in psoriasis patients, higher SAA level (β = 0.34, p = .02), KTR (β = 0.32, p = .02) and the PAr index (β = 0.29, p = .05) were associated with higher LV mass index independent of body mass index, hypertension and diabetes. Conclusion: Higher levels of the inflammatory biomarkers SAA, KTR and the PAr index were associated with greater LV mass index in psoriasis patients, indicating a role of chronic inflammation in LV remodelling evident even during treatment with TNF-α blockers.

Inflammation-Related Marker Profiling of Dietary Patterns and All-cause Mortality in the Melbourne Collaborative Cohort Study

BACKGROUND

Nutritional epidemiology research using self-reported dietary intake is prone to measurement error. Objective methods are being explored to overcome this limitation.

OBJECTIVES

We aimed to examine 1) the association between plasma markers related to inflammation and derive marker scores for dietary patterns [Mediterranean dietary score (MDS), energy-adjusted Dietary Inflammatory Index (E-DIITM), Alternative Healthy Eating Index 2010 (AHEI)] and 2) the associations of these marker scores with mortality.

METHODS

Weighted marker scores were derived from the cross-sectional association between 30 plasma markers and each dietary score (assessed using food-frequency questionnaires) using linear regression for 770 participants in the Melbourne Collaborative Cohort Study (aged 50-82 y). Prospective associations between marker scores and mortality (n = 249 deaths) were assessed using Cox regression (median follow-up: 14.4 y).

RESULTS

The MDS, E-DII, and AHEI were associated (P < 0.05) with 9, 14, and 11 plasma markers, respectively. Healthier diets (higher MDS and AHEI, and lower anti-inflammatory, E-DII) were associated with lower concentrations of kynurenines, neopterin, IFN-γ, cytokines, and C-reactive protein. Five of 6 markers common to the 3 dietary scores were components of the kynurenine pathway. The 3 dietary-based marker scores were highly correlated (Spearman ρ: -0.74, -0.82, and 0.93). Inverse associations (for 1-SD increment) were observed with all-cause mortality for the MDS marker score (HR: 0.84; 95% CI: 0.72-0.98) and the AHEI marker score (HR: 0.76; 95% CI: 0.66-0.89), whereas a positive association was observed with the E-DII marker score (HR: 1.18; 95% CI: 1.01-1.39). The same magnitude of effect was not observed for the respective dietary patterns.

CONCLUSIONS

Markers involved in inflammation-related processes are associated with dietary quality, including a substantial overlap between markers associated with the MDS, the E-DII, and the AHEI, especially kynurenines. Unfavorable marker scores, reflecting poorer-quality diets, were associated with increased mortality.

876Association of blood markers of inflammation, vitamin status and the kynurenine pathway with age and all-cause mortality

Background

Inflammation is a key feature of aging and a cause of numerous diseases. We investigated the association of 35 blood markers involved in inflammatory processes with age and mortality and developed a signature of ‘inflammaging’.

Methods

Thirty-five blood markers relating to the kynurenine pathway, vitamin status, and inflammation were measured in 976 participants in the Melbourne Collaborative Cohort Study at baseline (1990-1994, median age 59 years) and follow-up (2003-2007, median age 70 years). Associations of each marker with age and all-cause mortality were assessed using linear and Cox regression, respectively. A signature of inflammaging was obtained via Lasso regression of age on the markers and tested for association with mortality; we compared mortality associations for this signature and two weighted scores across all markers associated with age and mortality, respectively.

Results

Most markers (29/35) were associated with age, with strongest associations observed for cystatin C, neopterin, quinolinic acid, and the kynurenine/tryptophan ratio, PAr index, and 3-hydroxykynurenine/xanthurenic acid ratio. Many markers (14/35) showed strong associations with mortality in particular neopterin, quinolinic acid, HK/XA, PAr index, CRP, IL-6 and KTr. The inflammaging signature included six markers and showed strong association with mortality (HR = 1.5, 95%CI: 1.3-1.7), almost as strong as the association of weighted scores combining all measured markers.

Conclusions

Our study highlights the key role played by markers of the kynurenine pathway and vitamin B6 catabolism in aging, along with other well-established inflammation-related markers.

Key messages

A signature of ‘inflammaging’ based on 6 markers may be useful to better predict mortality.

Onasemnogene abeparvovec-xioi: a gene replacement strategy for the treatment of infants diagnosed with spinal muscular atrophy

In May of 2019, the adeno-associated virus (AAV)-based gene therapy onasemnogene abeparvovec-xioi (Zolgensma) became the second Food and Drug Administration (FDA)-approved gene therapy with designated use for infants diagnosed with spinal muscular atrophy (SMA). The decision came nearly 10 years after results of the first preclinical models were initially reported. While the journey was an arduous one, the approval was an indication of the remarkable success of the first in-human clinical trials. According to the traditional classification system of autosomal recessive SMA, of which there are multiple types with phenotypic variability, SMA type 1 is the most common and most severe and represents 45% of the SMA patient population. Children with SMA type 1 cannot lift their heads without assistance and do not live past their second birthday. With Zolgensma, the first treated children with SMA type 1 have reached 5 years of age and some of them achieved the ability to sit unassisted or even walk. In this article, we review the work that led to FDA approval with emphasis on the development of preclinical and clinical studies.

A novel case of impaired C-reactive protein response following open-heart surgery: A case report and review of the literature

BACKGROUND

C-reactive protein (CRP) is expected to increase in response to a range of inflammatory stimuli such as infections or extensive tissue trauma.

CASE REPORT

We present a novel case of severely impaired CRP response following NSTEMI, influenza A infection and open-heart surgery in which serum CRP concentrations remained < 1 mg/L during an observational period of 28 days.

CONCLUSION

To our knowledge, no previous publications exists describing patients with a lack of CRP response following cardiothoracic surgery. We believe this to be a novel finding warranting further investigations regarding the etiology and prevalence of this phenomenon.

Quantifying Precision Loss in Targeted Metabolomics Based on Mass Spectrometry and Nonmatching Internal Standards

In mass spectrometry, reliable quantification requires correction for variations in ionization efficiency between samples. The preferred method is the addition of a stable isotope-labeled internal standard (SIL-IS). In targeted metabolomics, a dedicated SIL-IS for each metabolite of interest may not always be realized due to high cost or limited availability. We recently completed the analysis of more than 70 biomarkers, each with a matching SIL-IS, across four mass spectrometry-based platforms (one GC-MS/MS and three LC-MS/MS). Using data from calibrator and quality control samples added to 60 96-well trays (analytical runs), we calculated analytical precision (CV) retrospectively. The use of integrated peak areas for all metabolites and internal standards allowed us to calculate precision for all matching analyte (A)/SIL-IS (IS) pairs as well as for all nonmatching A/IS pairs within each platform (total n = 1442). The median between-run precision for matching A/IS across the four platforms was 2.7-5.9%. The median CV for nonmatching A/IS (corresponding to pairing analytes with a non-SIL-IS) was 2.9-10.7 percentage points higher. Across all platforms, CVs for nonmatching A/IS increased with increasing difference in retention time (Spearman's rho of 0.17-0.93). The CV difference for nonmatching vs matching A/IS was often, but not always, smaller when analytes and internal standards were close structural analogs.

Vitamin and Mineral Status in a Vegan Diet

BACKGROUND

In Germany, public interest in a vegan diet is steadily growing. There are, however, no current data on the macro- and micronutrient status of vegans.

METHODS

In a cross-sectional study entitled "The Risks and Benefits of a Vegan Diet" (RBVD), we investigated the dietary intake, basic laboratory parameters, vitamin status, and trace-element status of 36 vegans and 36 persons on an omnivorous diet. Each group consisted of 18 men and 18 women aged 30-60.

RESULTS

Nearly all the vegans and one-third of the persons on a mixed diet had consumed supplements in the previous 4 weeks. Vegans and nonvegans had similar energy intake but differed in the intake of both macronutrients (e.g., dietary fiber) and micronutrients (e.g., vitamins B12, B2, D, E, and K, as well as folate, iodine, and iron). There were no intergroup differences in the biomarkers of vitamin B12, vitamin D, or iron status. The ferritin values and blood counts indicated iron deficiency in four vegans and three non-vegans. Measurements in 24-hour urine samples revealed lower calcium excretion and markedly lower iodine excretion in vegans compared to non-vegans; in one-third of the vegans, iodine excretion was lower than the WHO threshold value (<20 μg/L) for severe iodine deficiency.

CONCLUSION

Vitamin B12 status was similarly good in vegans and non-vegans, even though the vegans consumed very little dietary B12. This may be due to the high rate of supplementation. The findings imply a need to also assure adequate iodine intake in the population, especially among persons on a vegan diet.

Microheterogeneity and preanalytical stability of protein biomarkers of inflammation and renal function

Protein biomarker microheterogeneity has attracted increasing attention in epidemiological and clinical research studies. Knowledge concerning the preanalytical stability of proteins is paramount to assess the biological significance of their proteoforms. We investigated the stability of the inflammatory markers C-reactive protein (CRP), serum amyloid A (SAA), and calprotectin (S100A8/9), and the renal function marker, cystatin C (CnC). In total 16 proteoforms were quantified by immuno-MALDI-TOF MS in EDTA plasma and serum samples from 15 healthy volunteers. Prior to analysis blood samples were stored at either room temperature from 1 h up to 8 days, or underwent up to 9 consecutive freeze/thaw cycles. Pearson's correlation coefficient and t-test, intra-class correlation coefficient (ICC), and Autoregressive Integrated Moving-Average (ARIMA) models were used to investigate the stability of proteoform concentrations and distributions in blood. Plasma and serum concentrations of CRP and SAA proteoforms were highly stable during room temperature exposure and repeated freeze/thaw cycles, demonstrating excellent reproducibility (ICC > 0.75), no serial dependency in ARIMA models, and stable distribution of proteoforms. Stability analyses for proteoforms of S100A8/9 and CnC identified only minor preanalytical changes in concentrations and distributions, and none of the proteoforms were produced during prolonged exposure to room temperature or repeated freezing/thawing. The four proteins and their proteoforms are stable during sub-optimal sample handling, and represent robust biomarker candidates for future biobank studies aimed at investigating the microheterogeneity of SAA, S100A8/9, and CnC in relation to inflammation, renal dysfunction and various clinical outcomes.

Fitness is associated with lower inflammatory markers in obesity: the FATCOR study

Background

Obesity is associated with chronic low-grade inflammation, but exercise has anti-inflammatory properties. It is unknown whether the anti-inflammatory effects of fitness may influence the obesity-associated inflammation.

Purpose

To assess levels of inflammatory markers in fit vs. unfit overweight and obese subjects without known cardiovascular disease.

Methods

Peak oxygen uptake (VO2max) was measured by treadmill cardiopulmonary exercise testing in 566 subjects (mean age 48±9 years, 60% women) with body mass index &gt;27.0 kg/m2 in the FAT associated CardiOvasculaR dysfunction (FATCOR) study. Fitness was defined from age- and sex adjusted reference levels of VO2max. Serum levels of C-reactive protein (CRP), serum amyloid A (SAA) and calprotectin were assessed by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF) mass spectrometry and log transformed before inclusion in analyses.

Results

Fit subjects (n=147) were older and had less metabolic syndrome, obesity and hypertension compared to unfit subjects (n=419) (all p&lt;0.05). Serum levels of CRP and SAA were lower in fit subjects vs. unfit (p&lt;0.01), while serum calprotectin showed no difference (p=0.06). In multivariable logistic regression analyses, lower CRP (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.61–0.87, p&lt;0.001) and SAA (OR 0.61, 95% CI 0.40–0.93, p=0.02) remained associated with being fit after adjusting for age, sex, obesity, metabolic syndrome and hypertension. When looking at obese (n=357, fit n=53) and overweight subjects (n=209, fit n=94) separately, lower CRP (OR 0.60, 95% CI 0.46–0.78, p&lt;0.001) and SAA (OR 0.44, 95% CI 0.24–0.83, p=0.01) remained associated with being fit in obese, but not in overweight subjects after adjustment for age, sex and metabolic syndrome.

Conclusion

Fitness was associated with lower circulatory inflammatory markers in obesity independent of cardiometabolic risk factors. Our results suggest that fitness may promote cardiovascular benefit through the anti-inflammatory properties of exercise also in obesity.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Western Norway Regional Health Authority

In vitro activity of oritavancin alone or in combination against vancomycin-susceptible and -resistant enterococci

OBJECTIVES

The optimal treatment for serious infections due to Enterococcus spp. is unknown although combination antimicrobial therapy is often recommended for invasive infections to achieve bactericidal activity and improve clinical outcomes. Oritavancin is a novel lipoglycopeptide agent with in vitro activity against enterococci, including vancomycin-resistant VanA-type Enterococcus faecium. Data on its activity in combination with other antibacterials are limited. The objective of this study was to evaluate the activity of oritavancin alone and in combination with ceftriaxone, daptomycin, gentamicin, linezolid and rifampicin against vancomycin-susceptible and -resistant enterococci in in vitro time-kill analyses.

METHODS

Five enterococcal strains were used for all experiments: three vancomycin-resistant VanA-type E. faecium clinical bloodstream isolates, vancomycin-resistant VanA-type E. faecium ATCC 700221 and vancomycin-susceptible Enterococcus faecalis ATCC 29212. Individual drugs were tested at ¼, ½, 1, 2 and 4× MIC. Oritavancin combination experiments were performed with each agent at ¼× MIC.

RESULTS

Daptomycin was the most active single agent and was bactericidal against all strains at 4× MIC, followed by oritavancin, which was bactericidal against all three clinical VRE strains at ≥2× MIC. In combination experiments at ¼× MIC, oritavancin was synergistic with gentamicin against strains not displaying high-level aminoglycoside resistance. No other synergy against VRE strains was observed in any experiment. Strain- and drug-dependent antagonism was observed for many combinations.

CONCLUSIONS

These in vitro data do not support the routine use of combination therapy with oritavancin in the treatment of infections due to VRE.

Tryptophan catabolites as metabolic markers of vitamin B-6 status evaluated in cohorts of healthy adults and cardiovascular patients

BACKGROUND

Vitamin B-6 status is routinely measured as pyridoxal 5'-phosphate (PLP) in plasma. Low concentrations of PLP are associated with rheumatic, cardiovascular, and neoplastic diseases. We have previously shown that vitamin B-6 status affects the kynurenine (Kyn) pathway of tryptophan (Trp) catabolism.

OBJECTIVE

This study aimed to comprehensively evaluate the use of Kyns as potential markers of functional vitamin B-6 status across 2 large cohorts.

METHODS

We measured circulating concentrations of the first 6 metabolites in the Trp catabolic pathway by LC-MS-MS in the community-based Hordaland Health Study (HUSK; n = 7017) and cardiovascular patient-based Western Norway Coronary Angiography Cohort (WECAC; n = 4161). Cross-sectional and longitudinal associations of plasma PLP with Kyns were estimated using linear and nonlinear regression-based methods.

RESULTS

3'-Hydroxykynurenine (HK), a substrate, and all 4 products formed directly by the PLP-dependent enzymes kynurenine transaminase and kynureninase contributed to the explanation of circulating PLP in multivariable-adjusted regression models. The construct HK:(kynurenic acid + xanthurenic acid + 3'-hydroxyanthranilic acid + anthranilic acid), termed HK ratio (HKr), was related to plasma PLP with standardized regression coefficients (95% CIs) of -0.47 (-0.49, -0.45) and -0.46 (-0.49, -0.43) in HUSK and WECAC, respectively. Across strata of cohort and sex, HKr was 1.3- to 2.7-fold more sensitive, but also 1.7- to 2.9-fold more specific to changes in PLP than a previously proposed marker, HK:xanthurenic acid. Notably, the association was strongest at PLP concentrations < ∼20 nmol/L, a recognized threshold for vitamin B-6 deficiency. Finally, PLP and HKr demonstrated highly sex-specific and corroborating associations with age.

CONCLUSIONS

The results demonstrate that by combining 5 metabolites in the Kyn pathway into a simple index, HKr, a sensitive and specific indicator of intracellular vitamin B-6 status is obtained. The data also underscore the merit of evaluating alterations in Kyn metabolism when investigating vitamin B-6 and health.

Determination of Fumonisins B1 and B2 in Corn and Corn Flakes by Liquid Chromatography with Immunoaffinity Column Cleanup: Collaborative Study

A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from &lt;0.05 (blank) to 1.41 μg/g for FB1 and from &lt;0.05 to 0.56 μg/g for FB2, whereas in the corn flakes they ranged from &lt;0.05 to 1.05 μg/g for FB1 and from &lt;0.05 to 0.46 μg/g for FB2. The method involved double extraction with acetonitrile–methanol–water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21% for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 μg/g and with FB2 at 0.40 μg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.

P6373Serum amyloid A and left ventricular mass in psoriasis patients treated with infliximab

Background

Serum amyloid A (SAA) is an acute phase reactant associated with amyloid tissue deposition. Chronic skin inflammation in psoriasis could cause increased production of SAA in the liver and subsequent deposition in cardiac tissue.

Purpose

To assess if higher SAA is associated with higher left ventricular (LV) mass in psoriasis patients treated with infliximab

Methods

Data from 47 psoriasis patients treated with the tumour necrosis factor-α blocker infliximab (mean age 47±14 years, 66% men) was compared to 106 age and sex-matched control subjects (mean age 47±11 years, 70% men). LV mass was assessed by echocardiography and index to height m2.7. SAA was analysed by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight mass spectrometry.

Results

Psoriasis patients were more likely to be smokers than controls (38% vs. 16%, p=0.005), while other cardiovascular risk factors and SAA levels were similar. Psoriasis patients had lower LV mass index than controls (35.6±9.6 g/m2.7 vs. 40.3±9.8 g/m2.7, p=0.008). In the total study population, higher SAA level (β=0.23, p=0.003) was associated with higher LV mass index independent of presence of psoriasis (Table). In psoriasis patients, higher SAA level (β=0.48, p<0.001) was associated with higher LV mass index after adjustment for age and body mass index in multivariable analysis (Table). No association between SAA and LV mass index was found in controls.

Table 1. Multivariable associations of LV mass index in the total study population and in psoriasis patients Total study population Psoriasis LV mass index LV mass index R2=0.33, p<0.001 R2=0.43, p<0.001 β P β P Psoriasis −0.21 0.006 na na SAA, μg/ml 0.23 0.003 0.48 <0.001 BMI, kg/m2 0.39 <0.001 0.50 <0.001 Age, years 0.18 0.03 0.11 0.35 Female gender −0.11 0.15 – – Hypertension 0.08 0.35 – – Smoking 0.03 0.75 – – BMI, body mass index; LV, left ventricular; SAA, serum amyloid A; na, not applicable.

Conclusion

In psoriasis patients on infliximab treatment, higher SAA level was associated with greater LV mass index, pointing to a potential role of chronic inflammation and SAA production in the development of subclinical cardiac disease in psoriasis.

Acknowledgement/Funding

Western Regional Health Authority of Norway, Hjertefondet

Plasma Amino Acids and Incident Type 2 Diabetes in Patients With Coronary Artery Disease

OBJECTIVE

Altered plasma amino acid levels have been implicated as markers of risk for incident type 2 diabetes; however, amino acids are also related to established diabetes risk factors. Therefore, potential for confounding and the impact from competing risks require evaluation.

RESEARCH DESIGN AND METHODS

We prospectively followed 2,519 individuals with coronary artery disease but without diabetes. Mixed Gaussian modeling identified potential for confounding. Confounding, defined as a change in effect estimate (≥10%), was investigated by comparing amino acid-incident diabetes risk in a Cox model containing age and sex with that in models adjusted for potential confounders (BMI, estimated glomerular filtration rate, HDL cholesterol, triacylglycerol, C-reactive protein), which were further adjusted for plasma glucose, competing risks, and multiple comparisons (false discovery rate = 0.05, Benjamini-Hochberg method). Finally, component-wise likelihood-based boosting analysis including amino acids and confounders was performed and adjusted for competing risks in order to identify an optimal submodel for predicting incident diabetes.

RESULTS

The mean age of the source population was 61.9 years; 72% were men. During a median follow-up of 10.3 years, 267 incident cases of diabetes were identified. In age- and sex-adjusted models, several amino acids, including the branched-chain amino acids, significantly predicted incident diabetes. Adjustment for confounders, however, attenuated associations. Further adjustment for glucose and multiple comparisons rendered only arginine significant (hazard ratio/1 SD 1.21 [95% CI 1.07-1.37]). The optimal submodel included arginine and asparagine.

CONCLUSIONS

Adjustment for relevant clinical factors attenuated the amino acid-incident diabetes risk. Although these findings do not preclude the potential pathogenic role of other amino acids, they suggest that plasma arginine is independently associated with incident diabetes. Both arginine and asparagine were identified in an optimal model for predicting new-onset type 2 diabetes.

Therapeutic approach to chronic venous insufficiency - clinical benefits of red-vine-leaf-extract AS 195 (Antistax®)

Background: Chronic Venous Disorders or Diseases (CVD) of the lower extremities are a common finding affecting almost 90 % of an adult population. CVD includes varicose veins with a prevalence of approx. 25 %, overlapping with Chronic Venous Insufficiency (CVI) with a prevalence of approx. 17% in the adult population. CVI is characterized by venous pathology and objective signs like edema, skin changes or venous leg ulcers. Objective: To review and evaluate non-clinical and clinical data on a standardised herbal product containing flavonoids (AS195; Antistax^®) and to put them into a perspective with the pathophysiology of CVD. Methods: Literature available on non-clinical pharmacology and clinical studies with AS195 in CVI of the lower extremities was reviewed and described. Conclusion: Antistax^® is a well-described herbal product with standardised starting materials and manufacturing process. Its active ingredients accumulate in the venous intima, preserve the endothelial barrier function, and inhibit the inflammatory and prothrombotic cascade behind the progression of CVD. Its efficacy was analysed in adequately planned and executed clinical trials in patients with mild to moderately severe CVD (CEAP C1s to C4). AS195 showed a statistically significant and clinically relevant efficacy over placebo: in objective endpoints like volumetry of lower leg edema, but also in outcomes directly relevant for patients like tension and heaviness of the legs, tingling, and pain. Supportive studies confirmed and validated these results also for the broader population treated in daily practice. AS195 was well tolerated in studies and in everyday therapy. There are no known interactions with other medications. In the later stages, it can be used in combination with compression, complementing the beneficial haemodynamic effects of compression at a cellular level. AS195 is an addition to compression and closes a therapeutic gap especially in patients, who cannot use compression stockings, but still require CVD therapy.

Using metabolic profiling and gene expression analyses to explore molecular effects of replacing saturated fat with polyunsaturated fat-a randomized controlled dietary intervention study

BACKGROUND

Replacing dietary saturated fatty acids (SFAs) with polyunsaturated fatty acids (PUFA) reduces the plasma low-density lipoprotein (LDL) cholesterol and subsequently the risk of cardiovascular disease. However, beyond changes in LDL cholesterol, we lack a complete understanding of the physiologic alterations that occur when improving dietary fat quality.

OBJECTIVES

The aim of this study was to gain knowledge of metabolic alterations paralleling improvements in the fat quality of the diet.

METHODS

We recently conducted an 8-wk, double-blind, randomized controlled trial replacing SFAs with PUFAs in healthy subjects with moderate hypercholesterolemia (n = 99). In the present substudy, we performed comprehensive metabolic profiling with multiple platforms (both nuclear magnetic resonance- and mass spectrometry-based technology) (n = 99), and analyzed peripheral blood mononuclear cell gene expression (n = 95) by quantitative real-time polymerase chain reaction.

RESULTS

A large number of lipoprotein subclasses, myristoylcarnitine and palmitoylcarnitine, and kynurenine were reduced when SFAs were replaced with PUFAs. In contrast, bile acids, proprotein convertase subtilisin/kexin type 9, acetate, and acetoacetate were increased by the intervention. Some amino acids were also altered by the intervention. The mRNA levels of LXRA and LDLR were increased, in addition to several liver X receptor α target genes and genes involved in inflammation, whereas the mRNA levels of UCP2 and PPARD were decreased in peripheral blood mononuclear cells after replacing SFAs with PUFAs. Partial least squares-discriminant analysis showed that the 30 most important variables that contributed to class separation spanned all classes of biomarkers, and was in accordance with the univariate analysis.

CONCLUSIONS

Applying metabolomics in randomized controlled dietary intervention trials has the potential to extend our knowledge of the biological and molecular effects of dietary fat quality. This study was registered at clinicaltrials.gov as NCT01679496.

Bidirectional transfer of Anelloviridae lineages between graft and host during lung transplantation

Solid organ transplantation disrupts virus-host relationships, potentially resulting in viral transfer from donor to recipient, reactivation of latent viruses, and new viral infections. Viral transfer, colonization, and reactivation are typically monitored using assays for specific viruses, leaving the behavior of full viral populations (the "virome") understudied. Here we sought to investigate the temporal behavior of viruses from donor lungs and transplant recipients comprehensively. We interrogated the bronchoalveolar lavage and blood viromes during the peritransplant period and 6-16 months posttransplant in 13 donor-recipient pairs using shotgun metagenomic sequencing. Anelloviridae, ubiquitous human commensal viruses, were the most abundant human viruses identified. Herpesviruses, parvoviruses, polyomaviruses, and bacteriophages were also detected. Anelloviridae populations were complex, with some donor organs and hosts harboring multiple contemporaneous lineages. We identified transfer of Anelloviridae lineages from donor organ to recipient serum in 4 of 7 cases that could be queried, and immigration of lineages from recipient serum into the allograft in 6 of 10 such cases. Thus, metagenomic analyses revealed that viral populations move between graft and host in both directions, showing that organ transplantation involves implantation of both the allograft and commensal viral communities.

Breastfeeding and vitamin D supplementation reduce the risk of Kawasaki disease in a German population-based case-control study

Background

In Kawasaki disease (KD), a vasculitis of unknown etiology, the most serious complication is the development of coronary artery aneurysm (CAA). To date, the exact pathomechanism of KD is unknown. Both environmental and genetic factors seem to be associated with the development of the disease.

Methods

Data on KD patients recruited from the population-based German Pediatric Surveillance Study during 2012–2014 were used to evaluate the impact of various factors from the perinatal and infancy period on the development of KD. The study design was a matched case-control study with respect to age, sex and place of residence (n = 308 KD cases, n = 326 controls). All KD patients were individually re-evaluated; all fulfilled the international diagnostic KD criteria. A standardized questionnaire was used to review breastfeeding practices, vitamin D supplementation and birth characteristics. Logistic regression analyses were performed to obtain odds ratios (OR) for various risk factors among the case-control pairs. Simple measures of association were used to assess the impact of these factors on the clinical course.

Results

There was no difference in lengths of gestation, birth weight or parturition between KD patients and controls, but independently from each other vitamin D supplementation and breastfeeding were negatively associated with KD, even when adjusted for age, place of residence and sex. The duration of vitamin D was significantly shorter among children with KD than among children without KD (p = 0.039, OR = 0.964, 95% CI: 0.931–0.998), as was the duration of breastfeeding (p = 0.013, OR = 0.471, 95% CI: 0.260–0.853). Comparing KD patients with and without breastfeeding and/or vitamin D supplementation, there were no differences regarding developing CAA, being refractory to intravenous immunoglobulin treatment, age at onset of the disease and levels of inflammatory laboratory values.

Conclusion

Our findings indicate breastfeeding and vitamin D supplementation to have protective effects in association with KD in our study population; however, these seem not to influence the natural course of the disease. Although the overall effects were relatively small, they nevertheless underline the overall benefit of both interventions.

Trial registration

Clinical Trial Registration: German clinical trial registration, http://apps.who.int/trialsearch/Trial2.aspx?TrialID=DRKS00010071. Date of registration was 26. February 2016. The trial was registered retrospectively.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1438-2) contains supplementary material, which is available to authorized users.

Circulating high sensitivity C reactive protein concentrations and risk of lung cancer: nested case-control study within Lung Cancer Cohort Consortium

OBJECTIVES

To conduct a comprehensive analysis of prospectively measured circulating high sensitivity C reactive protein (hsCRP) concentration and risk of lung cancer overall, by smoking status (never, former, and current smokers), and histological sub-type.

DESIGN

Nested case-control study.

SETTING

20 population based cohort studies in Asia, Europe, Australia, and the United States.

PARTICIPANTS

5299 patients with incident lung cancer, with individually incidence density matched controls.

EXPOSURE

Circulating hsCRP concentrations in prediagnostic serum or plasma samples.

MAIN OUTCOME MEASURE

Incident lung cancer diagnosis.

RESULTS

A positive association between circulating hsCRP concentration and the risk of lung cancer for current (odds ratio associated with a doubling in hsCRP concentration 1.09, 95% confidence interval 1.05 to 1.13) and former smokers (1.09, 1.04 to 1.14) was observed, but not for never smokers (P<0.01 for interaction). This association was strong and consistent across all histological subtypes, except for adenocarcinoma, which was not strongly associated with hsCRP concentration regardless of smoking status (odds ratio for adenocarcinoma overall 0.97, 95% confidence interval 0.94 to 1.01). The association between circulating hsCRP concentration and the risk of lung cancer was strongest in the first two years of follow-up for former and current smokers. Including hsCRP concentration in a risk model, in addition to smoking based variables, did not improve risk discrimination overall, but slightly improved discrimination for cancers diagnosed in the first two years of follow-up.

CONCLUSIONS

Former and current smokers with higher circulating hsCRP concentrations had a higher risk of lung cancer overall. Circulating hsCRP concentration was not associated with the risk of lung adenocarcinoma. Circulating hsCRP concentration could be a prediagnostic marker of lung cancer rather than a causal risk factor.

The kynurenine pathway and cognitive performance in community-dwelling older adults. The Hordaland Health Study

INTRODUCTION

Tryptophan, its downstream metabolites in the kynurenine pathway and neopterin have been associated with inflammation and dementia. We aimed to study the associations between plasma levels of these metabolites and cognitive function in community-dwelling, older adults.

METHODS

This cross-sectional study included 2174 participants aged 70-72 years of the community-based Hordaland Health Study. Tryptophan, kynurenine, neopterin and eight downstream kynurenines were measured in plasma. Kendrick Object Learning Test (KOLT), Digit Symbol Test (DST) and the Controlled Oral Word Association Test (COWAT) were all outcomes in standardized Zellner's regression. The Wald test of a composite linear hypothesis of an association with each metabolite was adjusted by the Bonferroni method. Age, body mass index, C-reactive protein, depressive symptoms, diabetes, education, glomerular filtration rate, hypertension, previous myocardial infarction, prior stroke, pyridoxal 5'phosphate, sex and smoking were considered as potential confounders.

RESULTS

Higher levels of the kynurenine-to-tryptophan ratio (KTR) and neopterin were significantly associated with poorer, overall cognitive performance (p < 0.002). Specifically, KTR was negatively associated with KOLT (β -0.08, p = 0.001) and COWAT (β -0.08, p = 0.001), but not with DST (β -0.03, p = 0.160). This pattern was also seen for neopterin (KOLT: β -0.07; p = 0.001; COWAT: β -0.06, p = 0.010; DST: β -0.01, p = 0.800). The associations were not confounded by the examined variables. No significant associations were found between the eight downstream kynurenines and cognition.

CONCLUSION

Higher KTR and neopterin levels, biomarkers of cellular immune activation, were associated with reduced cognitive performance, implying an association between the innate immune system, memory, and language.

The Association between Objectively Measured Physical Activity and the Gut Microbiome among Older Community Dwelling Men

OBJECTIVES

To determine the relationship between objectively measured physical activity (PA) and the gut microbiome among community-dwelling older men.

DESIGN

Cross-sectional study.

SETTING

Osteoporotic Fractures in Men (MrOS) cohort participants at Visit 4 (2014-16).

PARTICIPANTS

Eligible men (n=373, mean age 84 y) included participants with 5-day activity assessment with at least 90% wear time and analyzed stool samples.

MEASUREMENTS

PA was measured with the SenseWear Pro3 Armband and stool samples analyzed for 16S v4 rRNA marker genes using Illumina MiSeq technology. Armband data together with sex, height, and weight were used to estimate total steps, total energy expenditure, and level of activity. 16S data was analyzed using standard UPARSE workflow. Shannon and Inverse Simpson indices were measures of (within-participant) α-diversity. Weighted and unweighted Unifrac were measures of (between-participant) β-diversity. We used linear regression analysis, principal coordinate analysis, zero-inflated Gaussian models to assess association between PA and α-diversity, β-diversity, and specific taxa, respectively, with adjustments for age, race, BMI, clinical center, library size, and number of chronic conditions.

RESULTS

PA was not associated with α-diversity. There was a slight association between PA and β-diversity (in particular the second principal coordinate). Compared to those who were less active, those who had higher step counts had higher relative abundance of Cetobacterium and lower relative abundance of taxa from the genera Coprobacillus, Adlercreutzia, Erysipelotrichaceae CC-115 after multivariable adjustment including age, BMI, and chronic conditions. There was no consistent pattern by phylum.

CONCLUSION

There was a modest association between levels of PA and specific gut microbes among community-dwelling older men. The observed associations are consistent with the hypothesis that underlying health status and composition of the host microbiome are related.

Renal function and blood pressure in 11 year old children born extremely preterm or small for gestational age

Background

Preterm birth and low birth weight are associated with reduced nephron numbers and increased risk of hypertension and kidney disease in later life.

Aims

We tested the hypothesis that extremely preterm birth and intrauterine growth restriction is associated with decreased renal function in mid childhood.

Methods

At 11 years of age the following measures were obtained in a regional cohort of children born extremely premature (EP, i.e. < 28 weeks gestational age—GA) or with extremely low birth weight (ELBW, i.e. BW < 1000 grams) and in matched controls born at term with appropriate BW (AGA): Height, weight, abdominal circumference, triceps and subscapular skin fold thicknesses, blood pressure, plasma levels of creatinine, cystatin C and symmetric dimethyl arginine (SDMA). Small for gestational age (SGA) was defined as a BW < 10^th percentile for GA. Glomerular filtration rate (GFR) was estimated according to the equations by Schwartz, Zappitelli and Gao.

Results

Fifty-seven of 61 eligible EP/ELBW children, 20 (35%) born SGA, and 54 controls, were assessed. Estimated GFR decreased while plasma SDMA increased from the children born AGA at term through those born preterm AGA to preterm SGA. Systolic BP was correlated to fat mass indices (p<0.03), but not to renal function (p>0.2) and did not differ between the groups.

Conclusions

Children born EP/ELBW, particularly those born SGA, had impaired renal function at age 11 years as judged from estimated GFRs and plasma levels of SDMA. Since reduced renal function is associated with an increased risk of later disease, these children should be followed in order to minimize additional risk factors.