Invasion of spontaneous germinal centers by naive B cells is rapid and persistent.

In autoreactive germinal centers (GC) initiated by a single rogue B cell clone, wild-type B cells expand and give rise to clones that target other autoantigens, known as epitope spreading. The chronic, progressive nature of epitope spreading calls for early interventions, but the kinetics and molecular requirements for wild-type B cell invasion and participation in GC remain largely unknown. With parabiosis and adoptive transfer approaches in a murine model of systemic lupus erythematosus, we demonstrate that wild-type B cells join existing GCs rapidly, clonally expand, persist, and contribute to autoantibody production and diversification. The invasion of autoreactive GCs required TLR7, B cell receptor specificity, antigen presentation, and type I interferon signaling. The adoptive transfer model provides a novel tool for identifying early events in the breaking of B cell tolerance in autoimmunity.

Editor's Choice - Nationwide Analysis of Patients Undergoing Iliac Artery Aneurysm Repair in the Netherlands.

OBJECTIVE: The new 2019 guideline of the European Society for Vascular Surgery (ESVS) recommends consideration for elective iliac artery aneurysm (eIAA) repair when the iliac diameter exceeds 3.5 cm, as opposed to 3.0 cm previously. The current study assessed diameters at time of eIAA repair and ruptured IAA (rIAA) repair and compared clinical outcomes after open surgical repair (OSR) and endovascular aneurysm repair (EVAR). METHODS: This retrospective observational study used the nationwide Dutch Surgical Aneurysm Audit (DSAA) registry that includes all patients who undergo aorto-iliac aneurysm repair in the Netherlands. All patients who underwent primary IAA repair between 1 January 2014 and 1 January 2018 were included. Diameters at time of eIAA and rIAA repair were compared in a descriptive fashion. The anatomical location of the IAA was not registered in the registry. Patient characteristics and outcomes of OSR and EVAR were compared with appropriate statistical tests. RESULTS: The DSAA registry comprised 974 patients who underwent IAA repair. A total of 851 patients were included after exclusion of patients undergoing revision surgery and patients with missing essential variables. eIAA repair was carried out in 713 patients, rIAA repair in 102, and symptomatic IAA repair in 36. OSR was performed in 205, EVAR in 618, and hybrid repairs and conversions in 28. The median maximum IAA diameter at the time of eIAA and rIAA repair was 43 (IQR 38-50) mm and 68 (IQR 58-85) mm, respectively. Mortality was 1.3% (95% CI 0.7-2.4) after eIAA repair and 25.5% (95% CI 18.0-34.7) after rIAA repair. Mortality was not significantly different between the OSR and EVAR subgroups. Elective OSR was associated with significantly more complications than EVAR (intra-operative: 9.8% vs. 3.6%, post-operative: 34.0% vs. 13.8%, respectively). CONCLUSION: In the Netherlands, most eIAA repairs are performed at diameters larger than recommended by the ESVS guideline. These findings appear to support the recent increase in the threshold diameter for eIAA repair.

Nasal and skin microbiomes are associated with disease severity in paediatric atopic dermatitis.

BACKGROUND: Alterations of the skin microbiome have been associated with atopic dermatitis (AD) and its severity. The nasal microbiome in relation to AD severity is less well studied. OBJECTIVES: We aimed to characterize the nasal and skin microbiomes in children with AD in relation to disease severity. In addition, we explored the differences and correlations between the nasal and skin communities. METHODS: We characterized the microbial composition of 90 nasal and 108 lesional skin samples cross-sectionally from patients with AD, using 16S-rRNA sequencing. In addition, a quantitative polymerase chain reaction was performed for Staphylococcus aureus and Staphylococcus epidermidis on the skin samples, and AD severity was estimated using the self-administered Eczema Area and Severity Index. RESULTS: We found an association between the microbial composition and AD severity in both the nose and skin samples (R2  = 2·6%; P = 0·017 and R2  = 7·0%; P = 0·004), strongly driven by staphylococci. However, other species also contributed, such as Moraxella in the nose. Skin lesions were positive for S. aureus in 50% of the children, and the presence and the load of S. aureus were not associated with AD severity. Although the nose and skin harbour distinct microbial communities (n = 48 paired samples; P < 0·001), we found that correlations exist between species in the nose and (other) species on the skin. CONCLUSIONS: Our results indicate that both the nasal and the skin microbiomes are associated with AD severity in children and that, next to staphylococci, other species contribute to this association.

Ranges of phenotypic flexibility in healthy subjects.

BACKGROUND: A key feature of metabolic health is the ability to adapt upon dietary perturbations. A systemic review defined an optimal nutritional challenge test, the "PhenFlex test" (PFT). Recently, it has been shown that the PFT enables the quantification of all relevant metabolic processes involved in maintaining or regaining homeostasis of metabolic health. Furthermore, it was demonstrated that quantification of PFT response was more sensitive as compared to fasting markers in demonstrating reduced phenotypic flexibility in metabolically impaired type 2 diabetes subjects. METHODS: This study aims to demonstrate that quantification of PFT response can discriminate between different states of health within the healthy range of the population. Therefore, 100 healthy subjects were enrolled (50 males, 50 females) ranging in age (young, middle, old) and body fat percentage (low, medium, high), assuming variation in phenotypic flexibility. Biomarkers were selected to quantify main processes which characterize phenotypic flexibility in response to PFT: flexibility in glucose, lipid, amino acid and vitamin metabolism, and metabolic stress. Individual phenotypic flexibility was visualized using the "health space" by representing the four processes on the health space axes. By quantifying and presenting the study subjects in this space, individual phenotypic flexibility was visualized. RESULTS: Using the "health space" visualization, differences between groups as well as within groups from the healthy range of the population can be easily and intuitively assessed. The health space showed a different adaptation to the metabolic PhenFlex test in the extremes of the recruited population; persons of young age with low to normal fat percentage had a markedly different position in the health space as compared to persons from old age with normal to high fat percentage. CONCLUSION: The results of the metabolic PhenFlex test in conjunction with the health space reliably assessed health on an individual basis. This quantification can be used in the future for personalized health quantification and advice.

Mesenchymal stem cell therapy in proteoglycan induced arthritis.

OBJECTIVES: To explore the immunosuppressive effect and mechanism of action of intraperitoneal (ip) and intra-articular (ia) mesenchymal stem cell (MSC) injection in proteoglycan induced arthritis (PGIA). METHODS: MSC were administered ip or ia after establishment of arthritis. We used serial bioluminescence imaging (BLI) to trace luciferase-transfected MSC. Mice were sacrificed at different time points to examine immunomodulatory changes in blood and secondary lymphoid organs. RESULTS: Both ip and local ia MSC injection resulted in a beneficial clinical and histological effect on established PGIA. BLI showed that MSC ip and ia in arthritic mice are largely retained for several weeks in the peritoneal cavity or injected joint respectively, without signs of migration. Following MSC treatment pathogenic PG-specific IgG2a antibodies in serum decreased. The Th2 cytokine IL-4 was only upregulated in PG-stimulated lymphocytes from spleens in ip treated mice and in lymphocytes from draining lymph nodes in ia treated mice. An increase in production of IL-10 was seen with equal distribution. Although IFN-γ was also elevated, the IFN-γ/IL-4 ratio in MSC treated mice was opposite to the ratio in (untreated) active PGIA. CONCLUSIONS: MSC treatment, both ip and ia, suppresses PGIA, a non-collagen induced arthritis model. MSC are largely retained for weeks in the injection region. MSC treatment induced at the region of injection a deviation of PG-specific immune responses, suggesting a more regulatory phenotype with production of IL-4 and IL-10, but also of IFN-γ, and a systemic decrease of pathogenic PG-specific IgG2a antibodies. These findings underpin the potential of MSC treatment in resistant arthritis.

[Differences between men and women in the composition of atherosclerotic plaque, as an explanation for the lower success rate of carotid endarterectomy in women]. / Verschillen in samenstelling van de atherosclerotische plaque tussen mannen en vrouwen als verklaring voor het geringere succes van carotisendarteriëctomie bij vrouwen.

OBJECTIVE: To determine whether men and women differ in the histological characteristics of plaque material removed at carotid endarterectomy. DESIGN: Observational and descriptive. METHODS: Carotid endarterectomy plaque specimens obtained from 45 degrees consecutive patients (135 women, 315 men) were assessed for the presence of macrophages, smooth muscle cells, collagen, calcifications, and luminal thrombus by means ofimmunohistochemical staining. The plaques were categorised in 3 phenotypes according to the overall presentation of histological characteristics and the lipid level. Protein was isolated from the plaques to determine the interleukin-6 (IL-6) and IL-8 concentrations and the activity of matrix metalloproteinase-8 (MMP-8) and MMP-9. RESULTS: Atheromatous plaques (> 40% fat) were less frequently observed in women than in men (22 versus 40%; p < 0.001). In addition, more women than men had a low macrophage staining (18 versus 11%; p = 0.05) and strong smooth muscle cell staining (38 versus 24%; p = 0.001). Compared with men, women had a lower plaque concentration of IL-8 and lower MMP-8 activity. The observed differences were most pronounced in the asymptomatic group. An atheromatous plaque occurred in 9% of asymptomatic women compared to 39% ofasymptomatic men (p = 0.02). Moreover, a large proportion of plaques obtained from asymptomatic women showed high smooth muscle cell content (53 versus 30%; p = 0.03) and high collagen content (55 versus 24%; p = 0.003). All relations between gender and plaque characteristics, except for MMP-8, remained the same in a multivariate analysis that was adjusted for clinical presentation and other cardiovascular risk factors. CONCLUSION: Women with a carotid stenosis had more stable plaques than men, independent of clinical presentation and cardiovascular risk profile. Asymptomatic women demonstrated the highest prevalence of stable plaques. These findings may explain why women benefit less from carotid endarterectomy than men.

Vascular occlusion as a late complication of the Angio-Seal closure device. A review of literature.

Although early vascular complications of the Angio-Seal closure device have been well described, little is known about late vascular complications due to this device. The aim of this paper is to discuss late femoral stenosis associated with the use of the Angio-Seal closure device. A literature search was performed using Medline', Embase' and The Cochrane Library' to identify relevant articles published up to the first of May 2007. Late occlusion was defined as an occlusion after approximately one week after Angio-Seal deployment. All together, eleven relevant papers were available. The reported prevalence of late vascular stenosis associated with Angio-Seal use varies between 1/961 and 4/175. Claudication was the most frequently reported complaint. In most cases, late stenosis due to the use of the Angio-Seal required surgery. Vascular obstruction due to the device has been reported up to 6 months after placement. In conclusion, vascular stenosis due to the use an Angio-Seal closure device is a complication that not only occurs in the first few days after placement, but also in the following months. In every patient developing complaints of arterial insufficiency after using an Angio-Seal, local arterial stenosis due to the device should be considered in the differential diagnosis. It therefore is important to register the use of the device in the patient chart.

Energy intake and micronutrient intake in elderly Europeans: seeking the minimum requirement in the SENECA study.

OBJECTIVE: To examine energy intake of elderly people participating in the Survey in Europe on Nutrition and the Elderly, a Concerted Action (SENECA) study in relation to the adequacy of micronutrient intake. DESIGN: Data from eight countries on 486 men and 519 women who were 74-79 years old. Dietary intakes of energy, iron, thiamine, riboflavin and pyridoxine were calculated. RESULTS: There was inadequate intake of one or more nutrients in 23.9% of men and 46.8% of women. The prevalence of inadequate intakes decreased gradually with higher energy intakes. Of all people with energy intakes exceeding 1500 kcal, 19% of men and 26% of women still had an inadequate intake of at least one micronutrient. CONCLUSION: We found no single criterion ensuring level of energy intake with an adequate micronutrient supply. The prevalence of an inadequate intake of micronutrients was high at all energy intake levels, especially in women.

Evaluation of the dietary history method used in the SENECA Study.

OBJECTIVE: To evaluate a modified dietary history method applied in elderly people aged 74-79 y. SETTING AND SUBJECTS: A total of 387 men and 420 women from seven European towns participated in an observational study. METHODS: Dietary intake was assessed with a modified dietary history and compared with a 3-day estimated record. RESULTS: The modified dietary history provided consistently higher intakes of energy and nutrients than the estimated record. For most nutrients this difference was between 10% and 20%. However, in some towns differences were much larger. Physical activity ratios calculated as reported energy intake divided by estimated basal metabolic rate (BMR) showed values less than 1.5 for data obtained with the estimated record, suggesting underreporting of energy intake. Pearson correlation coefficients between estimates by the two methods of the intakes of energy and almost all nutrients ranged from approximately 0.5 to 0.75. CONCLUSION: The size of the overall correlation coefficients indicates an acceptable agreement between the dietary history and record method in ranking individuals according to their intakes. For two towns, this agreement was not that good. Results indicate that the estimated record might not be a good reference method for older adults.

Criteria for reliable selection of the lowest level of amputation in peripheral vascular disease.

To improve the chances for the amputee to become ambulatory the most distal level of amputation should be selected in patients with end-stage peripheral vascular disease. Physical examination alone provides insufficient information when amputation levels are closely related to areas with signs and symptoms of ischemia. In the present series of 85 lower extremity amputations the predictive values of clinical parameters and skin perfusion pressure measurements are assessed. The role of clinical judgment is clarified: the most distal level of amputation is to be selected by physical examination, but further information is required to assess the healing potential at the selected level. The presence of palpable pulses immediately above the selected level correlates well with primary wound healing (p less than 0.001, negative predictive value 100%). The absence of palpable pulses and angiographic patency scores are of no clinical value in amputation level selection. Skin perfusion pressure measurements were of excellent predictive value (p less than 0.001, positive predictive value 89%, negative predictive value 99%). According to these data a strategy is proposed for routine determination of the lowest level of amputation, where primary wound healing can be expected.

Use of passive function testing in venous insufficiency: a prospective study.

In a prospective study, the results of venous function tests in 19 lower extremities with deep venous insufficiency and in seven control extremities were compared. First, the routine method of asking the patients to exercise their calves was used. Second, cuffs around the calves were rapidly inflated, producing standardized external compression to the calf muscle pump. Our aim was to decrease the influence of artifacts from involuntary muscle efforts and especially to render reproducible results of pressure reduction after passively pumping. The passive function test proved to be the only technique with which a decrease in pressure measured with strain gauges while the patient was in the standing position could significantly be discriminated between diseased and control extremities. Furthermore, the correlation of pressure decrease invasively versus measured noninvasively improved to 37% and thus became significant. Simulating calf venous pump function with the aid of inflatable cuffs is easily applicable in the vascular laboratory. It enables the vascular surgeon to reliably quantify venous recovery time and pressure reduction.

Construction of peritoneal venous valves: an experimental study in rats and piglets.

In the search for new techniques to improve venous valve insufficiency, a peritoneal patch with a mesothelial layer on either side was employed in the venous circulation to construct a venous valve de novo. This material was used because of the resemblance in fibrinolytic activity of mesothelial cells to endothelium. The behavior of double-sided flaps of peritoneum was first studied on only one side in the caval vein wall of 10 rats. All veins remained open, and smooth incorporation of the patch into the vein wall was observed. It was therefore decided to use the same material for construction of a cusp blade in the venous circulation. This venous reconstruction was microsurgically performed in 21 rats and 4 piglets. In our hands, intramuscular anesthesia proved superior to intraperitoneal analgesia in rats. For the piglets mechanical ventilation and general anesthesia were used. In 9 of 21 rats a fair or good result was observed, although it did not seem possible to create a fully competent valve with only one cusp blade in the 1.5-mm-diam caval veins. The same fact evolved from the study using four 7-mm-diam piglet veins. All peritoneal flaps in the venous circulation demonstrated rebuilding of their structure, perhaps induced by the relatively exaggerated central venous flow. To our knowledge, this technique has never been used before. It seems to offer many advantages in the venous circulation, where hardly any thrombogenic surface is tolerated in contrast to the arterial circulation. Application in humans is yet premature, but future research may resolve several problems that occurred in this study.

A multivariate analysis of determinants of wound healing in patients after amputation for peripheral vascular disease.

In a prospective study 53 patients undergoing amputations of the lower limb were evaluated for clinical criteria, laboratory results, pulse volume recordings, Doppler pressures, Photoplethysmographic Skin Perfusion Pressures (PPG/SPP) and angiography. The purpose of the study was to analyse which of these techniques predicts wound healing adequately after amputation. Forty-five patients eventually completed all tests. With the exception of PPG/SPP none of these tests were able to predict skin healing. The technique of PPG/SPP proved very reliable in helping to select the level of amputation, if measured anteriorly (P = 0.0001, r = 0.83). Angiographic scoring also correlated significantly (P = 0.0016) with a successful result. This study suggests that surgeons should not rely on their clinical acumen for the selection of the amputation level. In the absence of a reliable non-invasive test, angiography may well be useful but PPG/SPP will enable the surgeon to amputate on an optimal level and thus reduce complications and improve rehabilitation.

The correlation of peroperative outflow resistance measurements with patency 109 infrainguinal arterial reconstructions.

The predictive value of outflow resistance measurements for the patency of femoro-popliteal and femoro-crural bypass grafts was analysed. Peroperative outflow resistance measurements were performed in 109 infrainguinal arterial reconstructions. Outflow resistance was significantly higher in occluded bypasses compared with those which remained open (P less than 0.01), but there was a considerable overlap of values in both groups. Statistical analysis of the correlation between outflow resistance and patency rates at 3 months revealed a marginal correlation in the femoro-popliteal bypass group (R = -0.25), which was not significant (P = 0.064). In the femorocrural bypass group there was again only a marginal correlation (R = -0.27) but this was statistically significant (P = 0.05). These data demonstrate that intraoperative outflow resistance measurements are only of limited value for predicting bypass patency in individual cases.

Failure of quantitative venous photoplethysmography to assess venous insufficiency: a prospective clinical study.

The increase of deep venous reconstructive surgery necessitates reliable tests for evaluation of the results, which requires quantization of the expelled volume. This could only be done with invasive measurements, but now it seems possible to calibrate photoelectric cells, and quantize the results. Nineteen limbs of patients with deep venous disease and seven limbs of healthy volunteers were evaluated, with methods known from the literature. In addition to measurements in standing position, these methods were used in the more patient-friendly sitting position. Invasively and noninvasively measured recovery times correlated well in the standing (R = 0.83) and in the sitting position (R = 0.86). However, the quantization of expelled volume did not significantly correlate. Also, the differences between expelled volume of controls and patients were only significant with invasive measurements in the standing position (P = 0.006) as well as in the sitting position (P = 0.004). The differences were not significant with the noninvasive method. In our opinion, photoelectric cells still do not offer an alternative for invasive measurements in the evaluation of results after venous reconstructive surgery.