Cytomegalovirus Infection Facilitates the Costimulation of CD57+CD28- CD8 T Cells in HIV Infection and Atherosclerosis via the CD2-LFA-3 Axis

CD8 T cells are emerging as important mediators in atherosclerosis and cardiovascular disease (CVD). Immune activation may play a particular role in people with HIV (PWH) who are at an increased risk of CVD, even after controlling for known CVD risk factors. Latent CMV infection is associated with increased CVD risk for both PWH and people without HIV, and human CMV-specific CD4 and CD8 T cells are enriched for an immunosenescent phenotype. We previously showed that CMV coinfection in PWH promotes vascular homing and activation of inflammatory CD4 T cells through the CD2-LFA-3 axis. However, the role of CD2/LFA3 costimulation of CD8 T cells in PWH with CMV has yet to be described. In the present study, we demonstrate that CD2 expression on CX3CR1+CD57+CD28- inflammescent CD8 T cells is increased on cells from CMV-seropositive PWH. In vitro CD2/LFA-3 costimulation enhances TCR-mediated activation of these inflammatory CD8 memory T cells. Finally, we show that LFA-3 is highly expressed in aortas of SIV-infected rhesus macaques and in atherosclerotic plaques of people without HIV. Our findings are consistent with a model in which CMV infection enhances CD2 expression on highly proinflammatory CD8 T cells that can then be stimulated by LFA-3 expressed in the vasculature, even in the absence of CD28 costimulation. This model, in which CMV infection exacerbates toxic cytokine and granzyme production by CD8 T cells within the vasculature, highlights a potential therapeutic target in atherosclerosis development and progression, especially for PWH.

Trends and outcomes associated with intravascular ultrasound use during femoropopliteal revascularization in the Vascular Quality Initiative

OBJECTIVE

Intravascular ultrasound (IVUS) use in lower extremity interventions is growing in popularity owing to its imaging in the axial plane, superior detail in imaging lesion characteristics, and its enhanced ability to delineate lesion severity and extent compared with catheter angiograms. However, there are conflicting data regarding whether IVUS affects outcomes. The purpose of this study was to assess the effect associated with IVUS implementation in femoropopliteal interventions.

METHODS

This retrospective cohort study used Vascular Quality Initiative data. Patients undergoing an index endovascular femoropopliteal revascularization from 2016 to 2021 were included. Patients were differentiated by whether or not IVUS was used to assess the femoropopliteal segment during intervention (no IVUS, IVUS). Propensity score matching, based on preoperative demographics and measures of disease severity was used. Primary outcomes were major amputation-free survival (AFS), femoropopliteal reintervention-free survival (RFS), and primarily patent survival (PPS) at 12 months.

RESULTS

IVUS use grew steadily throughout the study period, comprising 0.6% of interventions in 2016 and increasing to 8.2% of interventions by 2021; growth was most dramatic in ambulatory surgical center or office-based laboratory settings where IVUS use grew from 4.4% to 43% to 47% of interventions. In unmatched cohorts, patients receiving interventions using IVUS tended to have lower prevalence of multiple cardiovascular comorbidities (eg, congestive heart failure, hypertension, diabetes, and dialysis dependence) and presented more often with claudication and less often with chronic limb-threatening ischemia (CLTI). Intraoperatively, IVUS was used more often in complex femoropopliteal lesions (Transatlantic Intersociety grade D vs A), and more often in conjunction with stenting and/or atherectomy. IVUS use was associated with improved AFS, but similar RFS and PPS at 12 months. However, in multivariable analysis IVUS was not associated with any of the primary outcomes independently; rather, all outcomes were influenced primarily by CLTI, dialysis dependence, and prior major amputation status; technical outcomes (ie, RFS and PPS loss) were further driven by complexity of lesion (worse in Transatlantic Intersociety grade D vs A lesions) and treatment setting (ie, ambulatory surgical center or office-based laboratory setting associated with increased hazard for RFS and PPS loss).

CONCLUSIONS

IVUS implementation in femoropopliteal interventions is growing, with rapid adoption among interventions in ambulatory surgical centers and office-based laboratories. IVUS was not associated with an effect on technical outcomes at 12 months; improvement in major AFS was observed; however, multivariable analysis suggests this finding may be an effect of confounding by multiple factors highly associated with IVUS use, namely, in patients with lower prevalence of CLTI, dialysis dependence, and prior major amputations, thus conveying baseline lower risk for major amputation and death.

Multidisciplinary Approach to Venous Disease: Enhancing Patient Care and Trainee Education Through Collaboration

The full spectrum of venous disease poses a significant burden on individuals and health-care systems globally. Venous disease can lead to a wide range of symptoms based on the level of disease and underlying pathology. In general, underlying pathologies are due to nonthrombotic (reflux/obstructive) and thrombotic causes. Most conditions are a sequela of the long-term effects of chronic venous insufficiency, deep vein thrombosis (DVT), or nonthrombotic deep vein obstruction. The prevalence of venous disease is substantial, impacting the quality of life of a considerable proportion of the adult population. Untreated and progressive lower extremity venous disease can lead to venous ulceration and other complications. Additionally, poorly recognized and poorly understood venous conditions of the abdomen and pelvis leave many patients "orphaned" in health-care systems that lack expertise in complex venous conditions. Addressing the burden and breadth of venous disease requires comprehensive management approaches, early diagnosis, appropriate treatment interventions, and provider and patient education. Multidisciplinary collaborations and further research are essential to enhance our understanding, develop innovative therapies, and improve patient outcomes in the field of venous disease. In this paper, we highlight the importance of multidisciplinary collaboration and our journey to building an institutional venous team, as well as lessons learned.

Transient hexagonal structures in sheared emulsions of isotropic inclusions on smectic bubbles in microgravity conditions

We describe the collective behavior of isotropic droplets dispersed over a spherical smectic bubble, observed under microgravity conditions on the International Space Station (ISS). We find that droplets can form two-dimensional hexagonal structures changing with time. Our analysis indicates the possibility of spatial and temporal periodicity of such structures of droplets. Quantitative analysis of the hexagonal structure including the first three coordination circles was performed. A peculiar periodic-in-time ordering of the droplets, related to one-dimensional motion of droplets with non-uniform velocity, was found.

CX3CL1 and IL-15 Promote CD8 T cell chemoattraction in HIV and in atherosclerosis

Atherosclerotic cardiovascular disease (ASCVD) remains an important cause of morbidity in the general population and risk for ASCVD is increased approximately 2-fold in persons living with HIV infection (PLWH). This risk is linked to elevated CD8 T cell counts that are abundant in atherosclerotic plaques and have been implicated in disease pathogenesis yet the mechanisms driving T cell recruitment to and activation within plaques are poorly defined. Here we investigated the role of CD8 T cells in atherosclerosis in a non-human primate model of HIV infection and in the HIV-uninfected elderly; we sought to identify factors that promote the activation, function, and recruitment to endothelium of CX3CR1+ CD8 T cells. We measured elevated expression of CX3CL1 and IL-15, and increased CD8 T cell numbers in the aortas of rhesus macaques infected with SIV or SHIV, and demonstrated similar findings in atherosclerotic vessels of HIV-uninfected humans. We found that recombinant TNF enhanced the production and release of CX3CL1 and bioactive IL-15 from aortic endothelial cells, but not from aortic smooth muscle cells. IL-15 in turn promoted CX3CR1 surface expression on and TNF synthesis by CD8 T cells, and IL-15-treated CD8 T cells exhibited enhanced CX3CL1-dependent chemoattraction toward endothelial cells in vitro. Finally, we show that CD8 T cells in human atherosclerotic plaques have an activated, resident phenotype consistent with in vivo IL-15 and CX3CL1 exposure. In this report, we define a novel model of CD8 T cell involvement in atherosclerosis whereby CX3CL1 and IL-15 operate in tandem within the vascular endothelium to promote infiltration by activated CX3CR1+ memory CD8 T cells that drive further endothelial activation via TNF. We propose that these interactions are prevalent in aging and in PLWH, populations where circulating activated CX3CR1+ CD8 T cell numbers are often expanded.

Cytomegalovirus Coinfection Is Associated with Increased Vascular-Homing CD57+ CD4 T Cells in HIV Infection

Cytotoxic CD4 T cells are linked to cardiovascular morbidities and accumulate in both HIV and CMV infections, both of which are associated with increased risk of cardiovascular disease (CVD). In this study, we identify CMV coinfection as a major driver of the cytotoxic phenotype, characterized by elevated CD57 expression and reduced CD28 expression, in circulating CD4 T cells from people living with HIV infection, and investigate potential mechanisms linking this cell population to CVD. We find that human CD57+ CD4 T cells express high levels of the costimulatory receptor CD2 and that CD2/LFA-3 costimulation results in a more robust and polyfunctional effector response to TCR signals, compared with CD28-mediated costimulation. CD57+ CD4 T cells also express the vascular endothelium-homing receptor CX3CR1 and migrate toward CX3CL1-expressing endothelial cells in vitro. IL-15 promotes the cytotoxic phenotype, elevates CX3CR1 expression, and enhances the trafficking of CD57+ CD4 T cells to endothelium and may therefore be important in linking these cells to cardiovascular complications. Finally, we demonstrate the presence of activated CD57+ CD4 T cells and expression of CX3CL1 and LFA-3 in atherosclerotic plaque tissues from HIV-uninfected donors. Our findings are consistent with a model in which cytotoxic CD4 T cells contribute to CVD in HIV/CMV coinfection and in atherosclerosis via CX3CR1-mediated trafficking and CD2/LFA-3-mediated costimulation. This study identifies several targets for therapeutic interventions and may help bridge the gap in understanding how CMV infection and immunity are linked to increased cardiovascular risk in people living with HIV infection.

Cytomegalovirus coinfection is associated with increased vascular-homing CD57+ CD4 T cells in HIV infection

Cytotoxic CD4 T cells are linked to cardiovascular morbidities and accumulate in both human immunodeficiency virus (HIV) and cytomegalovirus (CMV) infections, both of which are associated with increased risk of cardiovascular disease. Here we identify CMV coinfection as a major driver of the cytotoxic phenotype – characterized by elevated CD57 expression and reduced CD28 expression – in circulating CD4 T cells from people living with HIV infection (PLWH). We find that CD57+ CD4 T cells express high levels of the costimulatory receptor CD2 and that CD2/LFA-3 costimulation results in a more robust and polyfunctional effector response to T cell receptor (TCR) signals, compared to CD28-mediated costimulation. CD57+ CD4 T cells also express the vascular endothelium-homing receptor CX3CR1 and migrate toward CX3CL1-expressing endothelial cells in vitro. IL-15 promotes the cytotoxic phenotype, elevates CX3CR1 expression, and enhances the trafficking of CD57+ CD4 T cells, and may therefore be important in linking these cells to cardiovascular complications. Finally, we demonstrate the presence of CD57+ CD4 T cells and expression of IL-15, CX3CL1, and LFA-3 in atherosclerotic plaque tissues from HIV-uninfected donors. Our findings are consistent with a model in which cytotoxic CD4 T cells contribute to cardiovascular disease in HIV/CMV coinfection and in atherosclerosis via CX3CR1-mediated trafficking and CD2-mediated costimulation, and may help bridge the gap in understanding how CMV infection and immunity are linked to increased cardiovascular risk in PLWH.

Acute Presentation of a Pseudoaneurysm After a Proximal Humerus Shaft Fracture: A Case Report

CASE

A 69-year-old woman presented with a brachial artery pseudoaneurysm causing median, ulnar, and radial nerve compressive neuropathies 8 weeks after a proximal humerus shaft fracture treated with intramedullary nailing. She underwent a brachial artery bypass with a reverse cephalic vein interposition graft and neurolysis after decompression of a large pseudoaneurysm. Postoperatively, the patient had a normal vascular examination with recovering neurological function.

CONCLUSIONS

A high index of suspicion for a brachial artery pseudoaneurysm should be maintained in patients with a displaced proximal humerus shaft fracture, particularly when an abnormal neurovascular examination is present.

Marangoni Flow in Freely Suspended Liquid Films

We demonstrate controlled material transport driven by temperature differences in thin freely suspended smectic films. Films with submicrometer thicknesses and lateral extensions of several millimeters were studied in microgravity during suborbital rocket flights. In-plane temperature differences cause two specific Marangoni effects, directed flow and convection patterns. At low gradients, practically thresholdless, flow transports material with a normal (negative) temperature coefficient of the surface tension dσ/dT<0 from the hot to the cold film edge, it accumulates at the cold film edge. In materials with dσ/dT>0, the reverse transport from the cold to the hot edge is observed. We present a model that describes the effect quantitatively. It predicts that not the temperature gradient in the film plane but the temperature difference between the thermopads is relevant for the effect.

Defect Interactions in Anisotropic Two-Dimensional Fluids

Disclinations in liquid crystals bear striking analogies to defect structures in a wide variety of physical systems, and their straightforward optical observability makes them excellent models to study fundamental properties of defect interactions. We employ freely suspended smectic-C films, which behave as quasi-two-dimensional polar nematics. A procedure to capture high-strength disclinations in localized spots is introduced. These disclinations are released in a controlled way, and the motion of the mutually repelling topological charges with strength +1 is studied quantitatively. We demonstrate that the classical models, which employ elastic one-constant approximation, fail to describe their dynamics correctly. In realistic liquid crystals, even small differences between splay and bend constants lead to the selection of pure splay or pure bend +1 defects. For those, the models work only in very special configurations. In general, additional director walls are involved which reinforce the repulsive interactions substantially.

Rupture and recoil of bent-core liquid crystal filaments

The recoil process of free-standing liquid crystal filaments is investigated experimentally and theoretically. We focus on two aspects, the contraction speed of the filament and a spontaneously formed undulation instability. At the moment of rupture, the filaments buckle similarly to the classical Euler buckling of elastic rods. The tip velocity decays with decreasing filament length. The wavelength of buckling affinely decreases with the retracting filament tip. The energy gain related to the decrease of the total length and surface area of the filaments is mainly dissipated by layer rearrangements during thickening of the fibre. A flow back into the meniscus is relevant only in the final stage of the recoil process. We introduce a model for the quantitative description of the filament retraction speed. The dynamics of this recoil behaviour may find relevance as a model for biology-related filaments.

Frustrated packing of spheres in a flat container under symmetry-breaking bias

We study statistical properties of packings of monodisperse spheres in a flat box. After "gravitational" filling and appropriate agitation, a nearly regular (in plane) but frustrated (normal to the plane) triangular lattice forms, where beads at individual sites touch either the front or back wall. It has striking analogies to order in antiferromagnetic Ising spin models. When tilting the container, Earth's gravitational field mimics external forces similar to magnetic fields in the spin systems. While packings in vertical containers adopt a frustrated state with statistical correlations between neighboring sites, the configurations continuously approach the predictions of a random Ising model when the cell tilt is increased. Our experiments offer insights into both the influence of geometrical constraints on random granular packing and a descriptive example of frustrated ordering.

Granular gases of rod-shaped grains in microgravity

Granular gases are convenient model systems to investigate the statistical physics of nonequilibrium systems. In the literature, one finds numerous theoretical predictions, but only few experiments. We study a weakly excited dilute gas of rods, confined in a cuboid container in microgravity during a suborbital rocket flight. With respect to a gas of spherical grains at comparable filling fraction, the mean free path is considerably reduced. This guarantees a dominance of grain-grain collisions over grain-wall collisions. No clustering was observed, unlike in similar experiments with spherical grains. Rod positions and orientations were determined and tracked. Translational and rotational velocity distributions are non-Gaussian. Equipartition of kinetic energy between translations and rotations is violated.

Two-dimensional microrheology of freely suspended liquid crystal films

Smectic liquid crystals form freely-suspended, fluid films of highly uniform structure and thickness, making them ideal systems for studies of hydrodynamics in two dimensions. We have measured particle mobility and shear viscosity by direct observation of the gravitational drift of silica spheres and smectic islands included in these fluid membranes. In thick films, we observe a hydrodynamic regime dominated by lateral confinement effects, with the mobility of the inclusion determined predominantly by coupling of the fluid flow to the fixed boundaries of the film. In thin films, the mobility of inclusions is governed primarily by coupling of the fluid to the surrounding air, as predicted by Saffman-Delbrück theory.

Novel in vitro model for assessing susceptibility of synthetic hernia repair meshes to Staphylococcus aureus infection using green fluorescent protein-labeled bacteria and modern imaging techniques

BACKGROUND

Mesh infection complicating hernia repair is a major cause of patient morbidity and results in substantial healthcare expenditures. The various constructs of prosthetic mesh may alter the ability of bacteria to attach and form a biofilm. Few data exist evaluating biofilm formation. Using the Maestro in-Vivo Imaging System (CRi, Inc., Woburn, MA) to detect green fluorescent protein (GFP)-expressing Staphylococcus aureus, we studied the ability of synthetic mesh to withstand bacterial biofilm formation in an in vitro model.

METHODS

We included four meshes: Polypropylene (PP), polypropylene/expanded PTFE (PX), compressed PTFE (cPTFE), and polyester/polyethylene glycol and collagen hydrogel (PE). Five samples of each mesh were exposed to GFP-expressing S. aureus for 18 h at 37°C. Next, green fluorescence was measured using the Maestro Imaging System, with the results expressed in relative fluorescence units (RFU), subtracting the fluorescence of uninfected mesh (control). Each mesh subsequently underwent sonication and quantitative culture of the released bacteria, with the results expressed in colony-forming units (CFU). Analysis of variance was performed to compare the mean values for the different meshes.

RESULTS

There was a statistically significant difference in bacterial fluorescence for the four meshes: PE (49.9 ± 25.5 [standard deviation] RFU), PX (30.8 ± 9.4 RFU), cPTFE (10.1 ± 4.0 RFU), and PP (5.8 ± 7.5 RFU)(p = 0.001). Bacterial counts also were significantly different: PE (2.2 × 10(8) CFU), PX (8.6 × 10(7) CFU), cPTFE (3.7 × 10(7) CFU), and PP (9.1 × 10(7) CFU)(p < 0.001).

CONCLUSION

Using novel imaging technology, this study documented significantly different amounts of S. aureus biofilm formation and proliferation on different mesh constructs, with good agreement between imaging and culture results. A multifilament woven mesh (PE) had the highest degree of biofilm formation. These findings are being evaluated in a clinical infection model.

Corona patterns around inclusions in freely suspended smectic films

We discuss the structure and physical origin of corona patterns observed around solid or liquid spherical inclusions in freely suspended smectic films. Such patterns are observed when droplets or solid beads of micrometer size are sprayed onto the films. They are found in the smectic C phase and in the smectic A phase above such a smectic C phase, but disappear, for example, at the transition into a lower-temperature smectic B phase. We show that these structures are equivalent to splay domains found in the meniscus of freely suspended films, originating from surface-induced spontaneous splay.

[Bedtime, television and computer habits of primary school children in Germany]

BACKGROUND

Pediatricians recommend daily sleep of at least ten hours for children aged 9 and 10 years. Sufficient sleep is necessary for maintaining the body's homeostasis, as well as for fixing memories and learning. Lack of sleep in children has been associated with a diminished school performance, reduced attention span, and obesity. Adulthood is influenced by childhood lifestyle habits. Data from 4th graders in 34 schools in Mainz and its surroundings were analysed in order to determine negative health lifestyle factors in German primary school children, such as lack of sleep and increased leisure time spent watching television and computer gaming.

METHODS

Data from a cross-sectional study regarding cellular phone use in fourth-graders in Mainz were used for this analysis. Bedtime, television and computer use habits, as well as other factors were explored. A total of 1933 children from 34 schools participated by answering a questionnaire in the 2002-2003 school year (participation rate: 88%). Complete data for the secondary analysis were available from 1889 students (51% male, median age 10 years).

RESULTS

Overall, 28% of the children reported going to bed after 9 pm on week nights, 16% reported watching television more than three hours daily, and 11% played computer or video games more than three hours daily. In the adjusted binary logistic regression model, being older, male, having older siblings, watching television (OR 1.82, 95% CI 1.28-2.61) and playing computer games (OR 3.23; 95% CI 2.24-4.67) for more than three hours daily, owning a mobile phone, and being in a school in the city were associated with going to bed after 9 pm.

CONCLUSION

Every fourth child does not obtain a sleep duration of 10 hours, under the assumption that primary schoolchildren need to be awake at 7 am on weekdays. Lifestyle factors that may negatively influence a child's development determine their actual and future habits. Sufficient sleep and less television and computer leisure times should be assertively emphasized to parents and carers of primary school students, in order to prevent the negative consequences of lack of sleep, such as diminished school performance. Developing sex-specific prevention programs, which take into account the complex lifestyles and habits of primary schoolchildren, seems to be relevant.