An altered plasma lipidome-phenome network characterizes heart failure with preserved ejection fraction

AIMS

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial, multisystemic syndrome that involves alterations in lipid metabolism. This study aimed to test whether distinct plasma lipid profiles or lipid entities or both are associated with clinical and functional echocardiographic parameters in HFpEF.

METHODS AND RESULTS

We examined the human plasma lipidome in HFpEF patients (n = 18) with left ventricular ejection fraction ≥50% and N-terminal pro-brain natriuretic peptide (NT-proBNP) >125 pg/mL and control subjects (n = 12) using mass spectrometry-based shotgun lipidomics. The cohort included 8 women and 22 men with average age of 67.8 ± 8.6 SD. The control and disease groups were not significantly different with respect to age, body mass index, systolic and diastolic blood pressure, and waist-to-hip ratio. The disease group experienced more fatigue (P < 0.001), had more often coronary artery disease (P = 0.04), and received more medications (beta-blockers, P < 0.001). The disease group had significantly different levels of HFpEF-relevant parameters, including NT-proBNP (P < 0.001), left ventricular mass index (P = 0.005), left atrial volume index (P = 0.001), and left ventricular filling index (P < 0.001), and lower left ventricular end-diastolic diameter (P = 0.014), with no difference in left ventricular ejection fraction. Significant differences in lipid profiles between HFpEF patients and controls could not be detected, including no significant differences in abundance of circulating lipids binned by carbon chain length or by double bonds, nor at the level of individual lipid species. However, there was a striking correlation between selected lipids with smoking status that was independent of disease status, as well as between specific lipids and hyperlipidaemia [with corresponding significance of either false discovery rate (FDR) <0.1 or FDR < 0.01]. In an exploratory network analysis of correlations, we observed significantly stronger correlations within the HFpEF group between individual lipids from the cholesterol ester and phosphatidylcholine (PC) classes and clinical/echocardiographic parameters such as left atrial volume index, left ventricular end-diastolic diameters, and heart rate (FDR < 0.1). In contrast, the control group showed significantly stronger negative correlations (FDR < 0.1) between individual species from the PC and sphingomyelin classes and left ventricular mass index or systolic blood pressure.

CONCLUSIONS

We did not find significant direct associations between plasma lipidomic parameters and HFpEF and therefore could not conclude that any specific lipids are biomarkers of HFpEF. The validation in larger cohort is needed to confidently conclude the absence of first-order associations.

Genomic attributes of airway commensal bacteria and mucosa

Microbial communities at the airway mucosal barrier are conserved and highly ordered, in likelihood reflecting co-evolution with human host factors. Freed of selection to digest nutrients, the airway microbiome underpins cognate management of mucosal immunity and pathogen resistance. We show here the initial results of systematic culture and whole-genome sequencing of the thoracic airway bacteria, identifying 52 novel species amongst 126 organisms that constitute 75% of commensals typically present in heathy individuals. Clinically relevant genes encode antimicrobial synthesis, adhesion and biofilm formation, immune modulation, iron utilisation, nitrous oxide (NO) metabolism and sphingolipid signalling. Using whole-genome content we identify dysbiotic features that may influence asthma and chronic obstructive pulmonary disease. We match isolate gene content to transcripts and metabolites expressed late in airway epithelial differentiation, identifying pathways to sustain host interactions with microbiota. Our results provide a systematic basis for decrypting interactions between commensals, pathogens, and mucosa in lung diseases of global significance.

The interplay between dietary fatty acids and gut microbiota influences host metabolism and hepatic steatosis

Dietary lipids can affect metabolic health through gut microbiota-mediated mechanisms, but the influence of lipid-microbiota interaction on liver steatosis is largely unknown. We investigate the impact of dietary lipids on human gut microbiota composition and the effects of microbiota-lipid interactions on steatosis in male mice. In humans, low intake of saturated fatty acids (SFA) is associated with increased microbial diversity independent of fiber intake. In mice, poorly absorbed dietary long-chain SFA, particularly stearic acid, induce a shift in bile acid profile and improved metabolism and steatosis. These benefits are dependent on the gut microbiota, as they are transmitted by microbial transfer. Diets enriched in polyunsaturated fatty acids are protective against steatosis but have minor influence on the microbiota. In summary, we find that diets enriched in poorly absorbed long-chain SFA modulate gut microbiota profiles independent of fiber intake, and this interaction is relevant to improve metabolism and decrease liver steatosis.

Sputum Microbiome and Chronic Obstructive Pulmonary Disease in a Rural Ugandan Cohort of Well-Controlled HIV Infection

Sub-Saharan Africa has increased morbidity and mortality related to chronic obstructive pulmonary disease (COPD). COPD among people living with HIV (PLWH) has not been well studied in this region, where HIV/AIDS is endemic. Increasing evidence suggests that respiratory microbial composition plays a role in COPD severity. Therefore, we aimed to investigate microbiome patterns and associations among PLWH with COPD in Sub-Saharan Africa. We conducted a cross-sectional study of 200 adults stratified by HIV and COPD in rural Uganda. Induced sputum samples were collected as an easy-to-obtain proxy for the lower respiratory tract microbiota. We performed 16S rRNA gene sequencing and used PICRUSt2 (version 2.2.3) to infer the functional profiles of the microbial community. We used a statistical tool to detect changes in specific taxa that searches and adjusts for confounding factors such as antiretroviral therapy (ART), age, sex, and other participant characteristics. We could cluster the microbial community into three community types whose distribution was shown to be significantly impacted by HIV. Some genera, e.g., Veillonella, Actinomyces, Atopobium, and Filifactor, were significantly enriched in HIV-infected individuals, while the COPD status was significantly associated with Gammaproteobacteria and Selenomonas abundance. Furthermore, reduced bacterial richness and significant enrichment in Campylobacter were associated with HIV-COPD comorbidity. Functional prediction using PICRUSt2 revealed a significant depletion in glutamate degradation capacity pathways in HIV-positive patients. A comparison of our findings with an HIV cohort from the United Kingdom revealed significant differences in the sputum microbiome composition, irrespective of viral suppression. IMPORTANCE Even with ART available, HIV-infected individuals are at high risk of suffering comorbidities, as shown by the high prevalence of noninfectious lung diseases in the HIV population. Recent studies have suggested a role for the respiratory microbiota in driving chronic lung inflammation. The respiratory microbiota was significantly altered among PLWH, with disease persisting up to 3 years post-ART initiation and HIV suppression. The community structure and diversity of the sputum microbiota in COPD are associated with disease severity and clinical outcomes, both in stable COPD and during exacerbations. Therefore, a better understanding of the sputum microbiome among PLWH could improve COPD prognostic and risk stratification strategies. In this study, we observed that in a virologically suppressed HIV cohort in rural Uganda, we could show differences in sputum microbiota stratified by HIV and COPD, reduced bacterial richness, and significant enrichment in Campylobacter associated with HIV-COPD comorbidity.

An interdisciplinary approach to characterize peanut-allergic patients-First data from the FOOD@ consortium

Background

Peanut allergy is a frequent cause of food allergy and potentially life‐threatening. Within this interdisciplinary research approach, we aim to unravel the complex mechanisms of peanut allergy. As a first step were applied in an exploratory manner the analysis of peanut allergic versus non‐allergic controls.

Methods

Biosamples were studied regarding DNA methylation signatures, gut microbiome, adaptive and innate immune cell populations, soluble signaling molecules and allergen‐reactive antibody specificities. We applied a scalable systems medicine computational workflow to the assembled data.

Results

We identified combined cellular and soluble biomarker signatures that stratify donors into peanut‐allergic and non‐allergic with high specificity. DNA methylation profiling revealed various genes of interest and stool microbiota differences in bacteria abundances.

Conclusion

By extending our findings to a larger set of patients (e.g., children vs. adults), we will establish predictors for food allergy and tolerance and translate these as for example, indicators for interventional studies.

Tolerance induction through non-avoidance to prevent persistent food allergy (TINA) in children and adults with peanut or tree nut allergy: rationale, study design and methods of a randomized controlled trial and observational cohort study

BACKGROUND

Peanuts (PN) and tree nuts (TN) are among the most frequent elicitors of food allergy and can lead to life-threatening reactions. The current advice for allergic patients is to strictly avoid the offending food independently of their individual threshold level, whereas sensitized patients without allergic symptoms should frequently consume the food to avoid (re-)development of food allergy. The aim of this trial is to investigate (I) whether the consumption of low allergen amounts below the individual threshold may support natural tolerance development and (II) to what extent regular allergen consumption in sensitized but tolerant subjects prevents the (re-)development of PN or TN allergy.

METHODS

The TINA trial consisting of (part I) a randomized, controlled, open, parallel group, single-center, superiority trial (RCT), and (part II) a prospective observational exploratory cohort study. Children and adults (age 1-67 years) with suspected or known primary PN and/or TN allergy will undergo an oral food challenge (OFC) to determine their clinical reactivity and individual threshold. In the RCT, 120 PN or TN allergic patients who tolerate ≥100 mg of food protein will be randomized (1:1 ratio) to consumption of products with low amounts of PN or TN on a regular basis or strict avoidance for 1 year. The consumption group will start with 1/100 of their individual threshold, increasing the protein amount to 1/50 and 1/10 after 4 and 8 months, respectively. The primary endpoint is the clinical tolerance to PN or TN after 1 year assessed by OFC. In the cohort study, 120 subjects sensitized to PN and/or TN but tolerant are advised to regularly consume the food and observed for 1 year. The primary endpoint is the maintenance of clinical tolerance to PN and/or TN after 1 year assessed by challenging with the former tolerated cumulative dose.

DISCUSSION

This clinical trial will help to determine the impact of allergen consumption versus avoidance on natural tolerance development and whether the current dietary advice for PN or TN allergic patients with higher threshold levels is still valid.

TRIAL REGISTRATION

German Clinical Trials Register; ID: DRKS00016764 (RCT), DRKS00020467 (cohort study). Registered on 15 January 2020, http://www.drks.de .

Tolerance induction through early feeding to prevent food allergy in infants with eczema (TEFFA): rationale, study design, and methods of a randomized controlled trial

Background

Up to 8% of all children in industrialized countries suffer from food allergies, whereas children with atopic eczema are affected considerably more frequently. In addition, the type and starting time of weaning foods seem to influence the development of food allergies. However, data from interventional studies on weaning are controversial.

The aim of this randomized-controlled clinical trial is to investigate, whether an early introduction of hen's egg (HE), cow’s milk (CM), peanut (PN), and hazelnut (HN) in children with atopic eczema can reduce the risk for developing food allergies in the first year of life.

Methods

This is a protocol for a randomized, placebo controlled, double blind, single-center clinical trial.

One hundred fifty infants with atopic eczema at 4–8 months of age will be randomized in a 2:1 manner into an active group that will receive rusk-like biscuit powder with HE, CM, PN, and HN (initially approximately 2 mg of each food protein) for 6–8 months or a placebo group, whose participants will receive the same rusk-like biscuit powder without HE, CM, PN, and HN on a daily basis. During the interventional period, the amount of allergens in the study product will be increased three times, each after 6 weeks. All study participants who are sensitized to HE, CM, PN, or HN at the end of the interventional period will undergo an oral food challenge to the respective food in a further visit.

Primary endpoint is IgE-mediated food allergy to at least one of the four foods (HE, CM, PN or HN) after 6–8 months of intervention (i.e., at around 1 year of age). Secondary endpoints include multiple food allergies, severity of eczema, wheezing, and sensitization levels against food allergens.

Discussion

This clinical trial will assess whether an early introduction of allergenic foods into the diet of children with atopic eczema can prevent the development of food allergies. This trial will contribute to update food allergy prevention guidelines.

Trial registration

German Clinical Trials Register DRKS00016770. Registered on 09 January 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06126-x.

Quantifying technical confounders in microbiome studies

AIMS

Recent technical developments have allowed the study of the human microbiome to accelerate at an unprecedented pace. Methodological differences may have considerable impact on the results obtained. Thus, we investigated how different storage, isolation, and DNA extraction methods can influence the characterization of the intestinal microbiome, compared to the impact of true biological signals such as intraindividual variability, nutrition, health, and demographics.

METHODS AND RESULTS

An observative cohort study in 27 healthy subjects was performed. Participants were instructed to collect stool samples twice spaced by a week, using six different methods (naive and Zymo DNA/RNA Shield on dry ice, OMNIgene GUT, RNALater, 95% ethanol, Zymo DNA/RNA Shield at room temperature). DNA extraction from all samples was performed comparatively using QIAamp Power Fecal and ZymoBIOMICS DNA Kits. 16S rRNA sequencing of the gut microbiota as well as qPCRs were performed on the isolated DNA. Metrics included alpha diversity as well as multivariate and univariate comparisons of samples, controlling for covariate patterns computationally. Interindividual differences explained 7.4% of overall microbiome variability, whereas the choice of DNA extraction method explained a further 5.7%. At phylum level, the tested kits differed in their recovery of Gram-positive bacteria, which is reflected in a significantly skewed enterotype distribution.

CONCLUSION

DNA extraction methods had the highest impact on observed microbiome variability, and were comparable to interindividual differences, thus may spuriously mimic the microbiome signatures of various health and nutrition factors. Conversely, collection methods had a relatively small influence on microbiome composition. The present study provides necessary insight into the technical variables which can lead to divergent results from seemingly similar study designs. We anticipate that these results will contribute to future efforts towards standardization of microbiome quantification procedures in clinical research.

Transverse syndrome as the dominant feature of solitary cervical plasmocytoma with dissemination

STUDY DESIGN

A case report of transverse syndrome secondary to compression from an intravertebral plasmocytoma.

OBJECTIVES

To report a rare case of cervical cord compression.

SETTING

Vienna, Austria.

CASE REPORT

A 47-year-old man presented with pain over the left scapula and subsequent development of pain and sensory disturbance. Investigations showed that the entire C7 vertebra was affected by a plasmocytoma. Decompression was carried out but no stabilisation of the spinal column was performed. Seven days after surgery the patient became paraplegic. Chemotherapy produced no improvement.

CONCLUSION

Transverse syndrome may be a dominant feature of plasmocytoma and may resolve after immediate decompression but may recur if the spinal column is not stabilised.

Clinical relevance of CagA-specific antibodies related to CagA status of Helicobacter pylori isolates using immunofluorescence test and PCR

BACKGROUND

The cagA (cytotoxin-associated gene A) protein is found in about 50% of Helicobacter pylori strains; its clinical relevance in gastroduodenal disease is uncertain.

PATIENTS AND METHODS

The frequency of IgG antibodies to cagA was studied by using a commercial Western blot assay in sera of 189 patients with endoscopically and histologically confirmed gastroduodenal disease. In addition, 38 H. pylori strains isolated from biopsies were analyzed by immunofluorescence test (IFT) and PCR for detection of cagA protein and cagA gene sequences, respectively.

RESULTS

54.3-60.0% of all patients with gastrointestinal diseases (chronic gastritis, gastric or duodenal ulcer and chronic duodenitis) and 28.6% with a normal mucosa were found to be positive for anti-cagA IgG antibodies. There was no significant difference in anti-cagA IgG seroprevalence between the different clinical entities. CagA-positive (cagA+) H. pylori strains were detected in 44.7% and 50% of the 38 isolates by PCR and IFT, respectively. 22 of 23 patients infected with cagA+ strains had anti-cagA antibodies. Using PCR as a gold standard, the sensitivity and specificity of the cagA IgG Western blot were 100.0% and 35.0%, respectively; the sensitivity and specificity of the cagA IFT were 76.5% and 71.4%, respectively. The incidence of the cagA+ H. pylori strains detected either by PCR or IFT was significantly higher (p < 0.05 and p < 0.01, respectiveLy) in patients with chronic duodenitis, gastric or duodenal ulcer compared to patients with chronic gastritis (66.7%, 80% and 30.4%, respectiveLy).

CONCLUSION

In this study the cagA-specific serological status in H. pylori infections as diagnosed by IgG Western blot was of no predictive value for severity of disease. In contrast, the cagA status of H. pylori isolates, diagnosed by IFT or PCR, was a predictive marker for severe disease and, therefore, also of clinical relevance in the assessment of the virulence of the infecting strain.

[Replacement of the anterior cruciate ligament by cold preserved bone-cruciate ligament-bone allotransplants. An experimental study in the sheep]

One ACL in each of 17 mature sheep was replaced with a deep-frozen bone-an ACL bone allograft. Allografts were obtained from skeletally mature sheep using a standard aseptic technique and stored deep frozen for at least 6 days (mean 21 days). Macroscopical, biomechanical, and histological changes were evaluated 12, 24, and 52 weeks following implantation. At autopsy all allograft ligaments were present and demonstrated no evidence of infection or immune reaction. We found slight arthrotic changes in 3 knees after 12 weeks, in 4 knees after 24 weeks, and in 3 knees after 52 weeks. Twelve weeks after the operation the maximum load of the allografts was 17.5% of the contralateral controls and increased to 20.9% after 24 weeks and to 32% of controls after 52 weeks. Ligament stiffness in the linear region also increased from 18.9% of control (12 weeks) to 32.5% after 52 weeks, whereas maximum load decreased from 112.2% of controls (12 weeks) to 98% of controls (52 weeks). Histologically, the allografts progressively matured with time, becoming nearly identical to normal ligaments at 52 weeks.

Effect of renal function on cytokine secretion of monocytes and lymphocytes

The effect of renal function on cytokine secretion capacity of mononuclear cells was analysed in patients who had not been subjected to any form of renal replacement therapy. The aim of the study was especially to determine whether there is a defect of monocyte function. The patients were divided into three groups of 12 on the basis of renal function: group I, serum creatinine 1.5-3 mg/dl; group II, 3-6 mg/dl; and group III, > 6 mg/dl. Serving as controls were 36 age- and sex-matched healthy volunteers. IL-1 beta, IL-6, TNF-alpha, IL-2 and IF-gamma concentrations were measured in the supernatants of stimulated and unstimulated cells isolated from the blood. Renal function was not found to have any effect on the secretion capacity of IL-2 and IF-gamma. However, the secretion capacity of IL-1 beta of lipopolysaccharide (LPS)-stimulated monocytes was reduced in patients of group III to 214 +/- 290 pg/ml, compared with 501 +/- 327 pg/ml in controls (P = 0.047). The effect was even more accentuated for IL-6 (group III: 5422 +/- 5116 pg/ml; controls: 16,319 +/- 12,474 pg/ml; P = 0.019). Spontaneous secretion levels did not change for any of the cytokines, and LPS-stimulated TNF-alpha secretion was also normal. Highly purified blood monocytes/macrophages were stained for CD14, HLA-DR, CD11c, and CD4. Neither the percentage of positive cells nor the fluorescence intensity, as measured by FACS, was influenced by renal function, and no correlation could be established between function and phenotype.(ABSTRACT TRUNCATED AT 250 WORDS)

Recombinant allergens for immunoblot diagnosis of tree-pollen allergy

Diagnosis of type I allergy essentially depends on the availability of defined allergens, which can be provided by recombinant deoxyribonucleic acid (DNA) technology. We have previously isolated the c(complementary)DNAs encoding the major birch-pollen allergen, Bet v I, and another allergen with a molecular weight of 14 kd that was identified as birch profilin and designated Bet v II. These cDNAs were isolated from a lambda gt11 expression library by screening with the serum IgE from allergic patients. To obtain expression in Escherichia coli of recombinant allergens without additional fused polypeptides, both cDNAs were inserted into the plasmid pKK223-3. E. coli cells expressing Bet v I and birch profilin (Bet v II) were used for the preparation of recombinant proteins. These proteins were tested for their IgE-binding properties on immunoblots with sera from 100 different birch pollen-allergic patients. All patients' sera, which reacted with the natural allergens, Bet v I and Bet v II, demonstrated an identical IgE-binding pattern to recombinant birch-pollen allergens. Recombinant allergens may therefore be useful for the setup of diagnostic tests that allow the discrimination of different IgE-binding patterns as well as for patient-tailored immunotherapy.

Common epitopes of birch pollen and apples--studies by western and northern blot

Eighty-three sera from patients with birch-pollen allergy were investigated for IgE antibodies against apple allergens by means of immunoblotting. In immunoblots, 81 patients (97.6%) exhibited IgE directed against the major allergen of birch, Bet v I (17 kd), and these patients also demonstrated IgE binding to apple allergens in the molecular weight range 17 to 18 kd. Inhibition studies by preincubation of sera with birch-pollen extract led to complete blocking of IgE binding to this 17 to 18 kd protein, whereas preincubation with apple extract could not diminish IgE binding to Bet V I. Furthermore, a 17 kd protein in apple extract could be detected by immunoblotting with a Bet v I-specific monoclonal antibody. Northern blotting with a Bet v I cDNA clone as a probe revealed cross-hybridization of birch and apple allergen coding nucleic acids under conditions of high stringency, suggesting significant homology of the nucleic acid level. Our results support the concept that antigens in birch pollen and apples share allergenic epitopes leading to IgE cross-reactivities that may cause clinical manifestations when a special threshold level of specific IgE antibodies is reached.

The immunological relationship of epitopes on major tree pollen allergens

The major allergens of birch (Bet v I), alder (Aln g I), hazel (Cor a I) and hornbeam (Car b I) were investigated by means of high-resolution two-dimensional electrophoresis combined with immunoblotting. Eleven sera derived from patients allergic to birch pollen as well as mouse monoclonal antibodies BIP 1 and BIP 4, raised against Bet v I, were used as probes. Human IgE antibodies detected 10 spots in birch (Mr 17 kDa, pI 4.9-5.9); four spots in alder (Mr 18.5 kDa, pI 4.7-5.3); four spots in hazel (Mr 17 kDa, pI 5.0-5.8); and 12 + 7 spots in hornbeam (Mr 16.5 kDa, pI 4.9-6.6 and Mr 18 kDa, pI 5.2-6.7), respectively, representing major allergens. Each patient tested reacted in a similar fashion with the spot cluster(s) of a certain allergen. BIP 1 detected the same spot clusters as patients' IgE. BIP 4 reacted with the 17-, 18.5- and 18-kDa spots of birch, alder and hornbeam, but did not react with the 17-kDa spots of hazel and the 16.5-kDa spots of hornbeam. In inhibition experiments with birch pollen extract as inhibitor, IgE binding to Bet v I, as well as to Aln g I, Cor a I and Car b I was abolished, thus suggesting that IgE binding to major tree pollen allergens is confined to shared epitopes. These findings indicate that it might be sufficient to use only Bet v I for diagnostic procedures as well as for immunotherapy in patients with tree pollen allergy.

Evaluation of immunotherapy-induced changes in specific IgE, IgG and IgG subclasses in birch pollen allergic patients by means of immunoblotting. Correlation with clinical response

Sera from 27 birch pollen-allergic patients who had undergone hyposensitization treatment for 22-41 months were studied by immunoblotting before and after therapy, whereby the levels of IgE, IgG and IgG1-4 antibodies directed against the major allergen Bet v I and minor allergens of birch pollen were monitored. The clinical benefit of immunotherapy (IT) was evaluated using a symptom specific questionnaire. In patients with good clinical response (responders, n = 18), as defined by improvement of symptoms, anti-Bet v I IgE antibodies were found to decrease in 10/18 patients (55.5%), whereas in 6/18 (33.3%) no change and in two cases (11.2%) an increase of specific IgE was observed. In the group of patients with unsatisfactory clinical outcome (non-responders, n = 9), 3/9 patients (33.3%) showed a decrease, 3/9 (33.3%) no change and 3/9 (33.3%) an increase in levels of IgE antibodies directed against Bet v I. In the case of minor allergens, 5/18 responders (27.7%) and 8/9 non-responders (88.8%) showed specific IgE before IT. In the responder group, no increase of specific IgE could be observed after IT. In non-responders, however, an increase of IgE directed against minor allergens was seen in 3/9 patients (33.3%). In all patients, regardless of therapeutical success, IT-induced elevated levels of specific IgG, IgG1 and in particular IgG4 directed against Bet v I were found. Regarding minor allergens, a heterogeneous pattern of IgG responses without significant correlation to clinical benefit was observed. Our results indicate that changes in IgG reactivity patterns against Bet v I and minor allergens, as shown by the immunoblot technique, did not correlate with good or bad clinical outcome.