New Iron Acquisition System in Bacteroidetes

Capnocytophaga canimorsus, a dog mouth commensal and a member of the Bacteroidetes phylum, causes rare but often fatal septicemia in humans that have been in contact with a dog. Here, we show that C. canimorsus strains isolated from human infections grow readily in heat-inactivated human serum and that this property depends on a typical polysaccharide utilization locus (PUL), namely, PUL3 in strain Cc5. PUL are a hallmark of Bacteroidetes, and they encode various products, including surface protein complexes that capture and process polysaccharides or glycoproteins. The archetype system is the Bacteroides thetaiotaomicron Sus system, devoted to starch utilization. Unexpectedly, PUL3 conferred the capacity to acquire iron from serotransferrin (STF), and this capacity required each of the seven encoded proteins, indicating that a whole Sus-like machinery is acting as an iron capture system (ICS), a new and unexpected function for Sus-like machinery. No siderophore could be detected in the culture supernatant of C. canimorsus, suggesting that the Sus-like machinery captures iron directly from transferrin, but this could not be formally demonstrated. The seven genes of the ICS were found in the genomes of several opportunistic pathogens from the Capnocytophaga and Prevotella genera, in different isolates of the severe poultry pathogen Riemerellaanatipestifer, and in strains of Bacteroides fragilis and Odoribacter splanchnicus isolated from human infections. Thus, this study describes a new type of ICS that evolved in Bacteroidetes from a polysaccharide utilization system and most likely represents an important virulence factor in this group.     

Site selection for fat autotransplantation: Some observations

The use of autologous fat for implantation has recently received renewed attention in the plastic surgery literature. Autologous fat reportedly has been used for the treatment of wrinkles and Romberg's disease, and for buttock and breast augmentation. While some measure of success has been achieved, many surgeons report that substantial resorption of fat tissue occurs at the site of implantation. There is lack of unanimity regarding the ideal site for extraction or injection in order to minimize fat resorption. Adipose tissue samples were taken from women undergoing surgical procedures on the abdomen, gluteal-femoral region, and breast. Facial adipose tissue samples from men and women were also analyzed. Adipocytes were isolated chemically and sized microscopically. Activity of the lipogenic enzyme adipose tissue lipoprotein lipase (ATLPL) was measured in frozen samples. Results suggest that femoral site samples are somewhat larger (NS) and have greater lipogenic activity (p<0.03) than other sites. In our study, small facial samples had very low or unmeasurable levels of ATLPL activity. Perhaps cell size and lipogenic activity should be considered when selecting tissues for autotransplantation.     

The evaluation of off-loading using a new removable oRTHOsis in DIABetic foot (ORTHODIAB) randomized controlled trial: study design and rationale

Background

Off-loading is essential for diabetic foot management, but remains understudied. The evaluation of Off-loading using a new removable oRTHOsis in DIABetic foot (ORTHODIAB) trial aims to evaluate the efficacy of a new removable device “Orthèse Diabète” in the healing of diabetic foot.

Methods/design

ORTHODIAB is a French multi-centre randomized, open label trial, with a blinded end points evaluation by an adjudication committee according to the Prospective Randomized Open Blinded End-point. Main endpoints are adjudicated based on the analysis of diabetic foot photographs. Orthèse Diabète is a new removable off-loading orthosis (PROTEOR, France) allowing innovative functions including real-time evaluation of off-loading and estimation of patients’ adherence. Diabetic patients with neuropathic plantar ulcer or amputation wounds (toes or transmetatarsal) are assigned to one of 2 parallel-groups: Orthèse Diabète or control group (any removable device) according to a central computer-based randomization. Study visits are scheduled for 6 months (days D7 and D14, and months M1, M2, M3, and M6). The primary endpoint is the proportion of patients whose principal ulcer is healed at M3. Secondary endpoints are: the proportion of patients whose principal ulcer is healed at M1, M2 and M6; the proportion of patients whose initial ulcers are all healed at M1, M2, M3, and M6; principal ulcer area reduction; time-related ulcer-free survival; development of new ulcers; new lower-extremity amputation; infectious complications; off-loading adherence; and patient satisfaction. The study protocol was approved by the French National Agency for Medicines and Health Products Safety, and by the ethics committee of Saint-Louis Hospital (Paris). Comprehensive study information including a Patient Information Sheet has been provided to each patient who must give written informed consent before enrolment. Monitoring, data management, and statistical analyses are providing by UMANIS Life Science (Paris), independently to the sponsor. Since 27/10/2013, 13 centres have agreed to participate in this study, 117 participants were included, and 70 have achieved the study schedules. The study completion is expected for the end of 2016, and the main results will be published in 2017.

Conclusion

ORTHODIAB trial evaluates an innovating removable off-loading device, seeking to improve diabetic foot healing (ClinicalTrials.gov identifier: NCT01956162).

     

Effect of distance feedback on pacing strategy and perceived exertion during cycling

PURPOSE: The aim of this study was to investigate whether providing incorrect distance feedback would alter pacing strategies, perceived exertion, and heart rate during 20-km cycling time trials (TT). METHODS: Well-trained cyclists (N=15) performed a peak power output (PPO) test, familiarization trial, and four 20-km cycling TT during which they were provided with only distance feedback using 1-km distance splits. For the control trial, subjects received accurate feedback at each kilometer split. In the increase trial, they received inaccurate feedback at 0.775 km for the first kilometer split with the distance increasing by 25 m each subsequent split up to 1.25 km in the final kilometer split. For the decrease trial, inaccurate feedback was provided at 1.25 km for the first kilometer split with the distance decreasing by 25 m each subsequent split up to 0.775 km in the final split. For the random trial, distance splits were randomized. RESULTS: No significant differences were found in the finishing times between trials. Pacing strategies were unaltered as suggested by similar power output profiles during all trials. RPE scores were also similar for all trials. However, average heart rate varied significantly between trials (P<0.05). CONCLUSIONS: These results suggest that exercise performance, pacing strategy, and RPE during a 20-km cycling TT are not altered by incorrect distance feedback. The data supported the existence of a pacing strategy that is set before exercise and that is unaffected by external distance feedback.     

Proinflammatory T helper type 17 cells are effective B-cell helpers

T helper type 17 (TH17) cells are highly proinflammatory effector T cells that are characterized by the production of high amounts of IL-17A, IL-17F, IL-21, and IL-22. Furthermore, TH17 cells have been associated with a number of autoimmune diseases. However, it is not clear whether TH17 cells can also serve as effective helper cells. Here we show that TH17 cells can function as B-cell helpers in that they not only induce a strong proliferative response of B cells in vitro but also trigger antibody production with class switch recombination in vivo. Transfer of TH17 cells into WT or T-cell receptor α–deficient mice, which lack endogenous T cells, induces a pronounced antibody response with preferential isotype class switching to IgG1, IgG2a, IgG2b, and IgG3, as well as the formation of germinal centers. Conversely, blockade of IL-17 signaling results in a significant reduction in both number and size of germinal centers. Whereas IL-21 is known to help B cells, IL-17 on its own drives B cells to undergo preferential isotype class switching to IgG2a and IgG3 subtypes. These observations provide insights into the unappreciated role of TH17 cells and their signature cytokines in mediating B-cell differentiation and class switch recombination.     

Arthritogenic antibodies specific for a major type II collagen triple-helical epitope bind and destabilize cartilage independent of inflammation

OBJECTIVE: To investigate the significance and pathogenic potential of a highly conserved major type II collagen triple-helical epitope-specific antibody (U1; amino acids 494-504) in vivo and in vitro in patients with early rheumatoid arthritis (RA) and in experimental animal models of collagen-induced arthritis (CIA). METHODS: U1-specific antibodies in sera from patients with early RA (with or without joint erosions) were analyzed. Disease progression in the CIA models in mice and rats with anti-U1 antibodies was compared. The pathogenicity of binding of monoclonal antibodies (mAb) UL1 and CIIF4 to the U1 epitope and the F4 epitope (aa 926-936), respectively, was compared in vivo and on chondrocyte cultures and preformed cartilage in vitro, using Fourier transform infrared microspectroscopy analysis. In addition, UL1-induced proteoglycan depletion in vivo in the presence and absence of the complement factor C5 was analyzed. RESULTS: Increased levels of U1 antibodies were observed in patients with early RA, especially in association with joint erosions. A significant correlation of U1-specific antibodies with disease progression was found in rats and mice with CIA. UL1 mAb induced, whereas CIIF4 mAb inhibited, the progression of arthritis. Similarly, UL1, but not CIIF4, impaired matrix synthesis on chondrocyte cultures and adversely affected preformed cartilage. Furthermore, UL1 induced significant proteoglycan depletion in vivo 3 days after injection, even in the absence of C5. CONCLUSION: Antibody epitope specificity contributes significantly to the development of arthritis, and the early pathogenic events operate independent of inflammation both in vitro and in vivo.