Focus on time: dynamic imaging reveals stretch-dependent cell relaxation and nuclear deformation.

Among the stimuli to which cells are exposed in vivo, it has been shown that tensile deformations induce specific cellular responses in musculoskeletal, cardiovascular, and stromal tissues. However, the early response of cells to sustained substrate-based stretch has remained elusive because of the short timescale at which it occurs. To measure the tensile mechanical properties of adherent cells immediately after the application of substrate deformations, we have developed a dynamic traction force microscopy method that enables subsecond temporal resolution imaging of transient subcellular events. The system employs a novel, to our knowledge, tracking approach with minimal computational overhead to compensate substrate-based, stretch-induced motion/drift of stretched single cells in real time, allowing capture of biophysical phenomena on multiple channels by fluorescent multichannel imaging on a single camera, thus avoiding the need for beam splitting with the associated loss of light. Using this tool, we have characterized the transient subcellular forces and nuclear deformations of single cells immediately after the application of equibiaxial strain. Our experiments reveal significant differences in the cell relaxation dynamics and in the intracellular propagation of force to the nuclear compartment in cells stretched at different strain rates and exposes the need for time control for the correct interpretation of dynamic cell mechanics experiments.

Tendon response to matrix unloading is determined by the patho-physiological niche.

Although the molecular mechanisms behind tendon disease remain obscure, aberrant stromal matrix turnover and tissue hypervascularity are known hallmarks of advanced tendinopathy. We harness a tendon explant model to unwind complex cross-talk between the stromal and vascular tissue compartments. We identify the hypervascular tendon niche as a state-switch that gates degenerative matrix remodeling within the tissue stroma. Here pathological conditions resembling hypervascular tendon disease provoke rapid cell-mediated tissue breakdown upon mechanical unloading, in contrast to unloaded tendons that remain functionally stable in physiological low-oxygen/-temperature niches. Analyses of the stromal tissue transcriptome and secretome reveal that a stromal niche with elevated tissue oxygenation and temperature drives a ROS mediated cellular stress response that leads to adoption of an immune-modulatory phenotype within the degrading stromal tissue. Degradomic analysis further reveals a surprisingly rich set of active matrix proteases behind the progressive loss of tissue mechanics. We conclude that the tendon stromal compartment responds to aberrant mechanical unloading in a manner that is highly dependent on the vascular niche, with ROS gating a complex proteolytic breakdown of the functional collagen backbone.

The Protein Mat(ters)-Revealing the Biologically Relevant Mechanical Contribution of Collagen- and Fibronectin-Coated Micropatterns.

Understanding cell-material interactions requires accurate characterization of the substrate mechanics, which are generally measured by indentation-type atomic force microscopy. To facilitate cell-substrate interaction, model extracellular matrix coatings are used although their tensile mechanical properties are generally unknown. In this study, beyond standard compressive stiffness estimation, we performed a novel tensile mechanical characterization of collagen- and fibronectin-micropatterned polyacrylamide hydrogels. We further demonstrate the impact of the protein mat on the tensile stiffness characterization of adherent cells. To our knowledge, our study is the first to uncover direction-dependent mechanical behavior of the protein coatings and to demonstrate that it affects cellular response relative to substrate mechanics.

The relationship between metastatic potential and in vitro mechanical properties of osteosarcoma cells.

Osteosarcoma is the most frequent primary tumor of bone and is characterized by its high tendency to metastasize in lungs. Although treatment in cases of early diagnosis results in a 5-yr survival rate of nearly 60%, the prognosis for patients with secondary lesions at diagnosis is poor, and their 5-yr survival rate remains below 30%. In the present work, we have used a number of analytical methods to investigate the impact of increased metastatic potential on the biophysical properties and force generation of osteosarcoma cells. With that aim, we used two paired osteosarcoma cell lines, with each one comprising a parental line with low metastatic potential and its experimentally selected, highly metastatic form. Mechanical characterization was performed by means of atomic force microscopy, tensile biaxial deformation, and real-time deformability, and cell traction was measured using two-dimensional and micropost-based traction force microscopy. Our results reveal that the low metastatic osteosarcoma cells display larger spreading sizes and generate higher forces than the experimentally selected, highly malignant variants. In turn, the outcome of cell stiffness measurements strongly depends on the method used and the state of the probed cell, indicating that only a set of phenotyping methods provides the full picture of cell mechanics.

Epidemiology of Opportunistic Infections in HIV Infected Patients on Treatment in Accredited HIV Treatment Centers in Cameroon.

BACKGROUND: The African continent accounts for over 70% of people infected with Human Immunodeficiency Virus (HIV). The HIV sero-prevalence rate in Africa is estimated at 4.3%. In developed countries, such as France, pneumocystis is indicative of AIDS in 30% of patients; however, in Africa, pulmonary tuberculosis (TB) is the most-documented opportunistic infection (OI) and the leading cause of death in HIV-infected patients. In 2016, Cameroon had 32,000 new cases of OI and 29,000 deaths as a result of these infections. However, there is little existing data on the epidemiological profile of OIs in Cameroon, which is why we conducted this study in accredited HIV treatment centers and care/treatment units in the two cities of Douala and Yaounde, Cameroon. METHODS: This was a retrospective descriptive and analytical study carried out in 12 accredited HIV treatment centers in the cities of Yaoundé and Douala, Cameroon, over a period of seven months from October 2017 to April 2018. A stratified sampling method was used with three sampling levels: the city, type of health facility and size of active files. Ethical clearance and administrative authorization were obtained from the appropriate authorities and data were collected using a pre-tested survey form. The data collected was entered and analyzed using Epi Info version 3.5.4. RESULTS: Out of a total of 1,617 HIV-infected patients sampled, 419 (25.9%) had at least one OI. Of these patients with an OI, 246 or 65% had a baseline CD4 count of <200/mm3. There was a significant relationship between the male gender and the onset of OI (OR = 1.47; p = 0.01). Age ≥ 50 years was associated with the occurrence of OI (OR = 2.57; p = 0.01). A CD4 count of <200/mm3 was also associated with the risk of developing an OI (OR = 3.12; p = <0.01). CONCLUSION AND GLOBAL HEALTH IMPLICATIONS: The prevalence of OI is high among people living with HIV (25.9%). Shingles was the most common OI found followed by pulmonary tuberculosis. Male gender, age ≥ 50 years, and CD4 <200/mm3 were the most common factors associated with the occurrence of these OI. These findings suggest that public health interventions for reducing HIV related co-morbidities (and implicitly mortality) should especially target the male gender for greater impact in addition to other measures.

Non-Occupational HIV Post-exposure Prophylaxis: A 10-Year Retrospective Review of Data Following Sexual Exposure From Yaounde Central Hospital, Cameroon.

BACKGROUND: Human Immunodeficiency Virus (HIV) post exposure prophylaxis (PEP) consists of administering antiretroviral therapy within 72 hours of viral exposure and continued for four weeks. PEP has been shown to be an important means of preventing and decreasing the number of new HIV infections in the general population. The purpose of this study was to describe the profile of patients who consulted at the HIV/AIDS Care and Treatment Center of the Yaounde Central Hospital (YCH) for PEP following non-occupational exposure to HIV. To attain our objective, we carried out a 10-year retrospective review of patient records of all persons who consulted for accidental HIV exposure at the YCH, Cameroon. METHODS: This study was an observational, retrospective analysis of hospital records of persons who consulted for PEP following accidental exposure to HIV in the outpatient HIV clinic at YCH between January 2007 and December 2016. Data extracted from patients' records were: type of HIV exposure, sex, age, profession, level of education, HIV status of source and time to consultation. Descriptive and inferential statistics were analyzed using STATA IC 12.0. Results were presented as median and interquartile range for continuous variables. Categorical variables were expressed as frequencies and proportions. RESULTS: There were 628 consultations for PEP of which 48% (299/628) were as a result of non-occupational post exposure prophylaxis (nPEP). Of those who consulted for HIV PEP following non-occupational exposure, 78% (234/299) were females; adolescents group (15-19 years) and young adults group (20 - 24yrs.) constituted 41% (125/299). Forty percent (1208/299) were secondary or high school students (level of education) and 88% (262/299) were non-healthcare workers. The median time-to-consultation for non-occupational PEP (nPEP) was 19 hours (IQR: 12.4-25.0) and HIV status of the source was unknown in 64% (191/299) of cases and positive for 8% (25/299) of cases. The most frequent indications for consulting were sexual assault, 75% (224/299); condom slippage or breakage, 10% (30/299); and unprotected consensual sexual intercourse, 15% (45/299). CONCLUSION AND GLOBAL HEALTH IMPLICATIONS: Consultations for nPEP are as frequent as those occupational PEP (48% vs 52% in this study) in clinical practice at YCH. A good history of the source is important as it prevents unnecessary prescriptions of ART (which themselves have potential side effects) for persons consulting for potential HIV non-occupational exposure. In our study, we found that 27% (82/299) unnecessary ART prescriptions were avoided by determining that the exposure source person had negative HIV status. In addition, adolescent or young females consulting for nPEP in clinics could be potential victims of sexual assault or gender-based violence. Where possible, we recommend that clinicians consider the source of suspected viral exposure in clinical practice prior to administering ART for PEP.

Biomaterial surface energy-driven ligand assembly strongly regulates stem cell mechanosensitivity and fate on very soft substrates.

Although mechanisms of cell-material interaction and cellular mechanotransduction are increasingly understood, the mechanical insensitivity of mesenchymal cells to certain soft amorphous biomaterial substrates has remained largely unexplained. We reveal that surface energy-driven supramolecular ligand assembly can regulate mesenchymal stem cell (MSC) sensing of substrate mechanical compliance and subsequent cell fate. Human MSCs were cultured on collagen-coated hydrophobic polydimethylsiloxane (PDMS) and hydrophilic polyethylene-oxide-PDMS (PEO-PDMS) of a range of stiffnesses. Although cell contractility was similarly diminished on soft substrates of both types, cell spreading and osteogenic differentiation occurred only on soft PDMS and not hydrophilic PEO-PDMS (elastic modulus <1 kPa). Substrate surface energy yields distinct ligand topologies with accordingly distinct profiles of recruited transmembrane cell receptors and related focal adhesion signaling. These differences did not differentially regulate Rho-associated kinase activity, but nonetheless regulated both cell spreading and downstream differentiation.

Identification of T-cell epitopes from benzylpenicillin conjugated to human serum albumin and implication in penicillin allergy.

BACKGROUND: There is in vitro evidence that T cells from allergic patients react to benzylpenicillin-human serum albumin (BP-HSA) bioconjugates. Our group has recently shown the existence of naïve CD4+ T cells recognizing BP-HSA in healthy donors. However, BP-haptenated peptides from HSA participating in the immunization of allergic patients have never been identified. The purpose of the present study is to identify immunodominant BP-haptenated peptides from HSA involved in immunization of patients to BP and to refine the frequency calculation of naïve CD4+ T cells recognizing BP. METHODS: Co-cultures were established with CD4+ T cells from non-allergic donors and mature autologous dendritic cells (DCs) loaded with BP-HSA or BP-haptenated peptides from HSA. The CD4+ T-cell response specific for BP-HSA or for individual BP-haptenated peptides was measured using an interferon-γ (IFN-γ) ELISpot assay. The frequency of BP-specific CD4+ T cells was then calculated using the Poisson distribution. BP-HSA and BP-haptenated peptides recognition by allergic patients was evaluated on peripheral blood mononuclear cells (PBMCs) using a lymphocyte transformation test (LTT). RESULTS: Results showed that BP-HSA and BP-haptenated peptides were recognized by naïve T cells from 15/16 and 13/14 tested healthy donors, respectively. Most donors responded to 3 peptides with BP covalently bound on lysines 159, 212, and 525. Two of these benzylpenicilloylated peptides (lysines 159 and 525) were also found to induce PBMCs proliferation in patients with allergic reaction to penicillins. CONCLUSION: This study identifies and characterizes for the first time the BP-haptenated peptides from HSA involved in the immunization of patients to penicillins.

High-resolution traction force microscopy on small focal adhesions - improved accuracy through optimal marker distribution and optical flow tracking.

The accurate determination of cellular forces using Traction Force Microscopy at increasingly small focal attachments to the extracellular environment presents an important yet substantial technical challenge. In these measurements, uncertainty regarding accuracy is prominent since experimental calibration frameworks at this size scale are fraught with errors - denying a gold standard against which accuracy of TFM methods can be judged. Therefore, we have developed a simulation platform for generating synthetic traction images that can be used as a benchmark to quantify the influence of critical experimental parameters and the associated errors. Using this approach, we show that TFM accuracy can be improved >35% compared to the standard approach by placing fluorescent beads as densely and closely as possible to the site of applied traction. Moreover, we use the platform to test tracking algorithms based on optical flow that measure deformation directly at the beads and show that these can dramatically outperform classical particle image velocimetry algorithms in terms of noise sensitivity and error. We then report how optimized experimental and numerical strategy can improve traction map accuracy, and further provide the best available benchmark to date for defining practical limits to TFM accuracy as a function of focal adhesion size.

Carboxylated nanodiamonds can be used as negative reference in in vitro nanogenotoxicity studies.

Nanodiamonds (NDs) are promising nanomaterials for biomedical applications. However, a few studies highlighted an in vitro genotoxic activity for detonation NDs, which was not evidenced in one of our previous work quantifying γ-H2Ax after 20 and 100 nm high-pressure high-temperature ND exposures of several cell lines. To confirm these results, in the present work, we investigated the genotoxicity of the same 20 and 100 nm NDs and added intermediate-sized NDs of 50 nm. Conventional in vitro genotoxicity tests were used, i.e., the in vitro micronucleus and comet assays that are recommended by the French National Agency for Medicines and Health Products Safety for the toxicological evaluation of nanomedicines. In vitro micronucleus and in vitro comet assays (standard and hOGG1-modified) were therefore performed in two human cell lines, the bronchial epithelial 16HBE14o- cells and the colon carcinoma T84 cells. Our results did not show any genotoxic activity, whatever the test, the cell line or the size of carboxylated NDs. Even though these in vitro results should be confirmed in vivo, they reinforce the potential interest of carboxylated NDs for biomedical applications or even as a negative reference nanoparticle in nanotoxicology. Copyright © 2017 John Wiley & Sons, Ltd.

Plasticity of the Leishmania genome leading to gene copy number variations and drug resistance.

Leishmania has a plastic genome, and drug pressure can select for gene copy number variation (CNV). CNVs can apply either to whole chromosomes, leading to aneuploidy, or to specific genomic regions. For the latter, the amplification of chromosomal regions occurs at the level of homologous direct or inverted repeated sequences leading to extrachromosomal circular or linear amplified DNAs. This ability of Leishmania to respond to drug pressure by CNVs has led to the development of genomic screens such as Cos-Seq, which has the potential of expediting the discovery of drug targets for novel promising drug candidates.

Deep-sequencing revealing mutation dynamics in the miltefosine transporter gene in Leishmania infantum selected for miltefosine resistance.

Miltefosine is the first oral drug used in chemotherapy against leishmaniasis. In vitro studies found that resistance to miltefosine in Leishmania is often associated with the acquisition of point mutations in the miltefosine transporter, leading to a decrease in drug uptake. In this study, the dynamics of mutations upon miltefosine selection was studied by deep-sequencing of the miltefosine transporter gene. Deep-sequencing data revealed that no mutation was detected in the miltefosine transporter at sub-inhibitory concentrations of miltefosine. We show that the prevalence of mutated alleles was increasing when the drug pressure heightened, that more mutations were observed in highly resistant mutants, and that most mutations remained when parasites were cultured for a few passages in the absence of miltefosine.

Chromosomal Translocations in the Parasite Leishmania by a MRE11/RAD50-Independent Microhomology-Mediated End Joining Mechanism.

The parasite Leishmania often relies on gene rearrangements to survive stressful environments. However, safeguarding a minimum level of genome integrity is important for cell survival. We hypothesized that maintenance of genomic integrity in Leishmania would imply a leading role of the MRE11 and RAD50 proteins considering their role in DNA repair, chromosomal organization and protection of chromosomes ends in other organisms. Attempts to generate RAD50 null mutants in a wild-type background failed and we provide evidence that this gene is essential. Remarkably, inactivation of RAD50 was possible in a MRE11 null mutant that we had previously generated, providing good evidence that RAD50 may be dispensable in the absence of MRE11. Inactivation of the MRE11 and RAD50 genes led to a decreased frequency of homologous recombination and analysis of the null mutants by whole genome sequencing revealed several chromosomal translocations. Sequencing of the junction between translocated chromosomes highlighted microhomology sequences at the level of breakpoint regions. Sequencing data also showed a decreased coverage at subtelomeric locations in many chromosomes in the MRE11-/-RAD50-/- parasites. This study demonstrates an MRE11-independent microhomology-mediated end-joining mechanism and a prominent role for MRE11 and RAD50 in the maintenance of genomic integrity. Moreover, we suggest the possible involvement of RAD50 in subtelomeric regions stability.

Intrachromosomal amplification, locus deletion and point mutation in the aquaglyceroporin AQP1 gene in antimony resistant Leishmania (Viannia) guyanensis.

BACKGROUND: Antimony resistance complicates the treatment of infections caused by the parasite Leishmania. METHODOLOGY/PRINCIPAL FINDINGS: Using next generation sequencing, we sequenced the genome of four independent Leishmania guyanensis antimony-resistant (SbR) mutants and found different chromosomal alterations including aneuploidy, intrachromosomal gene amplification and gene deletion. A segment covering 30 genes on chromosome 19 was amplified intrachromosomally in three of the four mutants. The gene coding for the multidrug resistance associated protein A involved in antimony resistance was also amplified in the four mutants, most likely through chromosomal translocation. All mutants also displayed a reduced accumulation of antimony mainly due to genomic alterations at the level of the subtelomeric region of chromosome 31 harboring the gene coding for the aquaglyceroporin 1 (LgAQP1). Resistance involved the loss of LgAQP1 through subtelomeric deletions in three mutants. Interestingly, the fourth mutant harbored a single G133D point mutation in LgAQP1 whose role in resistance was functionality confirmed through drug sensitivity and antimony accumulation assays. In contrast to the Leishmania subspecies that resort to extrachromosomal amplification, the Viannia strains studied here used intrachromosomal amplification and locus deletion. CONCLUSIONS/SIGNIFICANCE: This is the first report of a naturally occurred point mutation in AQP1 in antimony resistant parasites.

Formation of linear amplicons with inverted duplications in Leishmania requires the MRE11 nuclease.

Extrachromosomal DNA amplification is frequent in the protozoan parasite Leishmania selected for drug resistance. The extrachromosomal amplified DNA is either circular or linear, and is formed at the level of direct or inverted homologous repeated sequences that abound in the Leishmania genome. The RAD51 recombinase plays an important role in circular amplicons formation, but the mechanism by which linear amplicons are formed is unknown. We hypothesized that the Leishmania infantum DNA repair protein MRE11 is required for linear amplicons following rearrangements at the level of inverted repeats. The purified LiMRE11 protein showed both DNA binding and exonuclease activities. Inactivation of the LiMRE11 gene led to parasites with enhanced sensitivity to DNA damaging agents. The MRE11(-/-) parasites had a reduced capacity to form linear amplicons after drug selection, and the reintroduction of an MRE11 allele led to parasites regaining their capacity to generate linear amplicons, but only when MRE11 had an active nuclease activity. These results highlight a novel MRE11-dependent pathway used by Leishmania to amplify portions of its genome to respond to a changing environment.

DNA repair pathways in trypanosomatids: from DNA repair to drug resistance.

All living organisms are continuously faced with endogenous or exogenous stress conditions affecting genome stability. DNA repair pathways act as a defense mechanism, which is essential to maintain DNA integrity. There is much to learn about the regulation and functions of these mechanisms, not only in human cells but also equally in divergent organisms. In trypanosomatids, DNA repair pathways protect the genome against mutations but also act as an adaptive mechanism to promote drug resistance. In this review, we scrutinize the molecular mechanisms and DNA repair pathways which are conserved in trypanosomatids. The recent advances made by the genome consortiums reveal the complete genomic sequences of several pathogens. Therefore, using bioinformatics and genomic sequences, we analyze the conservation of DNA repair proteins and their key protein motifs in trypanosomatids. We thus present a comprehensive view of DNA repair processes in trypanosomatids at the crossroads of DNA repair and drug resistance.

Enhancing optical field intensities in Gaussian-profile fiber Bragg gratings.

Gaussian profile fiber Bragg gratings exhibit narrow-bandwidth transmission peaks with significant group delay at the edge of their photonic bandgap. We demonstrate group delays ranging from 0.2 to 5.6 ns from a 1.2 cm structure. Simulations suggest such a device would be capable of enhancing the field intensity of incoming light by a factor of 800. Enhancement is confirmed by photothermally induced bistability of these peaks even at sub-milliwatt input powers with as much as a four-fold difference in the magnitude of their responses. The strong field intensities of these modes could significantly enhance desired nonlinear optical responses in fiber, provided the impact of absorption is addressed.

Clinical and biological characteristics of diabetic patients under age 40 in Cameroon: relation to autoantibody status and comparison with Belgian patients.

AIMS: We investigated the prevalence of diabetes autoantibodies (Abs) in Cameroonian patients and controls, assessed their contribution in disease classification and compared results with data from Belgium. METHODS: Abs against GAD (GADA), IA-2 (IA-2A) and zinc transporter 8 (ZnT8A) were assessed in 302 recently diagnosed Cameroonian patients with diabetes and 184 control subjects without diabetes aged below 40 years. RESULTS: Only 27 (9%) Cameroonian patients were younger than 15 years. Overall, 29% of patients presented at least one diabetes-associated antibody vs 9% in healthy controls (24% vs 7% for GADA (p<0.001), 10% vs 3% for IA-2A (p<0.006), 4% vs 2% for ZnT8A). Ab(+) patients had lower C-peptide levels (p<0.001), were more often insulin-treated (p<0.002) and were as frequently diagnosed with type 1 diabetes as Ab(-) patients. Only 43% of Ab(+) patients aged 15-39 years were clinically classified as having type 1 diabetes in Cameroon vs 96% in Belgium (p<0.001). Not one Ab(+) Cameroonian patient carried HLA-DQ2/DQ8 genotype vs 23% of Belgian Ab(+) patients (p<0.001). Younger age at diagnosis and antibody positivity were independent predictors of insulin therapy. Ab(+) Cameroonian patients were older (p<0.001), had higher BMI (p<0.001) and lower Ab titers than Belgian Ab(+) patients. In ketonuric patients, prevalence of autoantibodies was similar as in non-ketonuric patients. CONCLUSIONS: In Cameroonian patients with diabetes aged under 40 years, antibody-positivity is not clearly related to disease phenotype, but may help predict the need for insulin treatment.

Identification and frequency of circulating CD4(+) T lymphocytes specific to Benzylpenicillin in healthy donors.

BACKGROUND: Drug hypersensitivity is known to rely on a drug-specific T-cell response. Amplitude of antigen-specific T-cell response is partly controlled by the size of the antigen-specific naïve CD4(+) T-cell repertoire, but estimate of this repertoire has never been investigated for allergenic drugs. The purpose of this study was to evaluate the frequency of benzylpenicillin-specific CD4(+) T lymphocytes in healthy donors. METHODS: Co-cultures were established with CD4(+) T lymphocytes from healthy donors and mature autologous dendritic cells loaded with benzylpenicillin coupled to human serum albumin. CD4(+) T lymphocytes were stimulated once a week for 4 weeks with benzylpenicillin coupled to human serum albumin. The CD4(+) T-cell response was measured using an interferon-γ ELISPOT assay. Frequency of benzylpenicillin-specific naive CD4(+) T lymphocytes was then calculated using the Poisson distribution law. RESULTS: Results showed the presence of benzylpenicillin-specific CD4(+) T lymphocytes in 9 of 10 tested healthy donors irrespective of their HLA typing, with a mean frequency of 0.29 cells per million of CD4(+) T cells. Experiments performed on naive (CD45RA(+) ) and on memory (CD45RO(+) ) CD4(+) T lymphocytes showed that these benzylpenicillin-specific CD4(+) T lymphocytes belonged to the naive T-cell subpopulation. CONCLUSION: This study showed for the first time the existence of naive CD4(+) T lymphocytes specific to benzylpenicillin in healthy donors.

Xylo-oligosaccharide (XOS) in combination with inulin modulates both the intestinal environment and immune status in healthy subjects, while XOS alone only shows prebiotic properties.

The purpose of the present study was to establish the prebiotic effect of a new xylo-oligosaccharide (XOS) and of an inulin-and-XOS mixture (INU-XOS) and to determine their effect on endotoxaemia (lipopolysaccharides (LPS)) and immune parameters. In this randomised, parallel, placebo-controlled, double-blind study, sixty healthy volunteers were randomly assigned to three groups, receiving either 5 g XOS, INU-XOS (3 g inulin +1 g XOS) or an equivalent weight of wheat maltodextrin (placebo) during 4 weeks. Faecal samples were collected to assess the effects of these products on microbiota, as well as SCFA composition, enzymatic activities and secretory IgA production. Circulating LPS was measured in plasma samples, and whole blood was incubated with LPS to measure cytokine expression. Consumption of XOS alone increased the faecal concentrations of Bifidobacterium and butyrate and activities of α-glucosidase and ß-glucuronidase, while decreasing the concentrations of acetate and p-cresol. Consumption of XOS in combination with inulin did not decrease the concentrations of acetate and p-cresol, but increased in addition the faecal concentrations of total SCFA and propionate. Furthermore, consumption of XOS in combination with inulin decreased LPS concentrations in blood and attenuated LPS-induced increases in gene expression in IL-1ß and LPS-induced decreases in gene expression in IL-13 in blood. In conclusion, consumption of XOS alone or in combination with inulin results in beneficial albeit different changes in the intestinal microbiome on a high-fat diet. In addition, consumption of XOS in combination with inulin attenuates the proinflammatory effects of a high-fat diet in the blood of healthy subjects.