Species difference of CD137 ligand signaling in human and murine monocytes

Background

Stimulation of CD137 ligand on human monocytes has been shown to induce DC differentiation, and these CD137L-DCs are more potent than classical DCs, in stimulating T cell responses in vitro. To allow an in vivo evaluation of the potency of CD137L-DCs in murine models we aimed at generating murine CD137L-DCs.

Methodology/Principal Findings

When stimulated through CD137 ligand murine monocytes responded just as human monocytes with an increased adherence, morphological changes, proliferation and an increase in viable cell numbers. But CD137 ligand signaling did not induce expression of inflammatory cytokines and costimulatory molecules in murine monocytes and these cells had no T cell stimulatory activity. Murine monocytes did not differentiate to inflammatory DCs upon CD137 ligand signaling. Furthermore, while CD137 ligand signaling induces maturation of human immature classical DCs it failed to do so with murine immature classical DCs.

Conclusions/Significance

These data demonstrate that both human and murine monocytes become activated by CD137 ligand signaling but only human and not murine monocytes differentiate to inflammatory DCs.     

Pregnancy and Preeclampsia Affect Monocyte Subsets in Humans and Rats

Introduction

Both nonclassical and intermediate monocytes have been implicated in different inflammatory conditions. We hypothesized that these monocytes would increase during pregnancy, a condition associated with generalized activation of inflammatory responses and that they would increase even more during preeclampsia, in which inflammatory responses are further stimulated. In the present study we investigated changes in monocyte subsets during healthy pregnancy and preeclampsia in humans and rats.

Methods

Blood monocyte subsets of nonpregnant, preeclamptic and healthy pregnant women were identified with CD14 and CD16. In nonpregnant and pregnant rats, blood monocytes were identified with CD172a and CD43, as well as in rats infused with adenosine triphosphate (ATP), a pro-inflammatory stimulus known to induce preeclampsia-like symptoms. Total and CD206-positive macrophages were quantified in placentas of these animals.

Results

Lower percentages of classical monocytes were found in pregnant women (91%–[83–98%]) compared to nonpregnant women (94%–[90–98%]) and even less in preeclamptic patients (90%–[61–92%]). In contrast, the percentage of combined nonclassical/intermediate monocytes was higher in pregnant women (8.5%–[2.3–16.6%] vs. 5.6%–[1.9–9.5%]) and even higher in preeclamptic patients (9.9%–[7.8–38.7%]), which was caused by a selective increase of intermediate monocytes. In rats, we also found lower percentages of classical monocytes and higher percentages of nonclassical monocytes in pregnant versus nonpregnant rats. ATP infusion increased the percentage of nonclassical monocytes in pregnant rats even further but not in nonpregnant rats. These nonclassical monocytes showed a more activated phenotype in pregnant ATP-infused rats only. Mesometrial triangles of ATP-infused rats had less CD206-positive macrophages as compared to those of saline-infused rats.

Conclusion

The higher percentage of nonclassical/intermediate monocytes found in pregnancy and preeclampsia confirms their association with inflammatory responses. The observation that ATP stimulated numbers/activation of nonclassical monocytes in pregnant rats only, suggests that nonclassical monocytes are specifically altered in pregnancy and may play a role in the pathophysiology of preeclampsia.     

Outcomes of a Geriatric Liaison Intervention to Prevent the Development of Postoperative Delirium in Frail Elderly Cancer Patients: Report on a Multicentre,Randomized, Controlled Trial

Background

Delirium is a serious and common postoperative complication, especially in frail elderly patients. The aim of this study was to evaluate the effect of a geriatric liaison intervention in comparison with standard care on the incidence of postoperative delirium in frail elderly cancer patients treated with an elective surgical procedure for a solid tumour.

Methods

Patients over 65 years of age who were undergoing elective surgery for a solid tumour were recruited to a multicentre, prospective, randomized, controlled trial. The patients were randomized to standard treatment versus a geriatric liaison intervention. The intervention consisted of a preoperative geriatric consultation, an individual treatment plan targeted at risk factors for delirium, daily visits by a geriatric nurse during the hospital stay and advice on managing any problems encountered. The primary outcome was the incidence of postoperative delirium. The secondary outcome measures were the severity of delirium, length of hospital stay, complications, mortality, care dependency, quality of life, return to an independent preoperative living situation and additional care at home.

Results

In total, the data of 260 patients were analysed. Delirium occurred in 31 patients (11.9%), and there was no significant difference between the incidence of delirium in the intervention group and the usual-care group (9.4% vs. 14.3%, OR: 0.63, 95% CI: 0.29–1.35).

Conclusions

Within this study, a geriatric liaison intervention based on frailty for the prevention of postoperative delirium in frail elderly cancer patients undergoing elective surgery for a solid tumour has not proven to be effective.

Trial Registration

Nederlands Trial Register Trial ID NTR 823     

CD56+ monocytes have a dysregulated cytokine response to lipopolysaccharide and accumulate in rheumatoid arthritis and immunosenescence

Introduction

Peripheral blood monocytes are no longer regarded as a homogeneous cell population, but can be differentiated both phenotypically and functionally into various subpopulations. In rheumatoid arthritis, the subpopulation of CD14^bright/CD16+ monocyte is expanded and prone towards generation of Th17 cells. CD56+ monocytes represent a different subpopulation, which is also expanded in conditions associated with autoimmunity like inflammatory bowel diseases. The aim of the study was the quantification and functional characterization of the CD56+ monocyte subset in rheumatoid arthritis (RA).

Methods

Frequencies of peripheral blood monocyte subpopulations were analyzed by flow cytometry in 86 healthy controls and 75 RA patients. In 16 patients, anti-tumor necrosis factor (TNF) therapy was initiated, and the CD56+ monocyte frequency was monitored longitudinally. Lipopolysaccharide (LPS)-induced cytokine production of CD56+ and CD56– monocytes was determined by intracellular staining or cytokine secretion assays.

Results

In healthy individuals, 8.6% ± 0.6 of the monocytes co-expressed CD56, with the majority of CD56+ monocytes being CD14^bright (7.9% ± 0.5), while only a minor population was CD14^dim (0.7% ± 0.1). We found a strong positive correlation between an individual’s age and the frequency of CD56+ monocytes. Upon stimulation with LPS, CD56+ monocytes became more frequently positive for TNF, IL-10 and IL-23 than CD56– monocytes. In addition, CD56+ monocytes spontaneously produced more reactive oxygen intermediates than CD56- monocytes. In RA patients, the frequency of CD56+ monocytes was significantly higher than in healthy controls (12.2% ± 0.9 vs. 7.9% ± 0.5, p = 0.0002), and this difference most pronounced in RA patients below 40 years of age (11.1% ± 1.6 vs. 4.1% ± 0.4, P < 0.0001). Treatment of the patients with an anti-TNF blocking agent significantly reduced CD56+ monocyte frequencies (baseline 12.4% vs. 24 weeks treatment 8.0%, P = 0.0429), and the magnitude of this decrease was found to correlate with the change in disease activity under the therapy.

Conclusion

The CD14^bright/CD56+ monocyte subset is expanded in aging individuals as well as in patients with RA. The pro-inflammatory production of cytokines and reactive oxygen species as well as the elimination of those cells in patients with a good response towards TNF inhibiting agents indicates a possible contribution of those monocytes in the inflammatory response in RA.     

Elderly subjects have a delayed antibody response and prolonged viraemia following yellow fever vaccination: a prospective controlled cohort study

Background

Yellow fever vaccination (YF-17D) can cause serious adverse events (SAEs). The mechanism of these SAEs is poorly understood. Older age has been identified as a risk factor. We tested the hypothesis that the humoral immune response to yellow fever vaccine develops more slowly in elderly than in younger subjects.

Method

We vaccinated young volunteers (18–28 yrs, N = 30) and elderly travelers (60–81 yrs, N = 28) with YF-17D and measured their neutralizing antibody titers and plasma YF-17D RNA copy numbers before vaccination and 3, 5, 10, 14 and 28 days after vaccination.

Results

Ten days after vaccination seroprotection was attained by 77% (23/30) of the young participants and by 50% (14/28) of the elderly participants (p = 0.03). Accordingly, the Geometric Mean Titer of younger participants was higher than the GMT of the elderly participants. At day 10 the difference was +2.9 IU/ml (95% CI 1.8–4.7, p = 0.00004) and at day 14 +1.8 IU/ml (95% CI 1.1–2.9, p = 0.02, using a mixed linear model. Viraemia was more common in the elderly (86%, 24/28) than in the younger participants (60%, 14/30) (p = 0.03) with higher YF-17D RNA copy numbers in the elderly participants.

Conclusions

We found that elderly subjects had a delayed antibody response and higher viraemia levels after yellow fever primovaccination. We postulate that with older age, a weaker immune response to yellow fever vaccine allows the attenuated virus to cause higher viraemia levels which may increase the risk of developing SAEs. This may be one piece in the puzzle of the pathophysiology of YEL-AVD.

Trial Registration

Trialregitser.nl NTR1040     

Transcript and Protein Analysis Reveals Better Survival Skills of Monocyte-Derived Dendritic Cells Compared to Monocytes during Oxidative Stress

Background

Dendritic cells (DCs), professional antigen-presenting cells with the unique ability to initiate primary T-cell responses, are present in atherosclerotic lesions where they are exposed to oxidative stress that generates cytotoxic reactive oxygen species (ROS). A large body of evidence indicates that cell death is a major modulating factor of atherogenesis. We examined antioxidant defence systems of human monocyte-derived (mo)DCs and monocytes in response to oxidative stress.

Methods

Oxidative stress was induced by addition of tertiary-butylhydroperoxide (tert-BHP, 30 min). Cellular responses were evaluated using flow cytometry and confocal live cell imaging (both using 5-(and-6)-chloromethyl-2,7-dichlorodihydrofluorescein diacetate, CM-H₂DCFDA). Viability was assessed by the neutral red assay. Total RNA was extracted for a PCR profiler array. Five genes were selected for confirmation by Taqman gene expression assays, and by immunoblotting or immunohistochemistry for protein levels.

Results

Tert-BHP increased CM-H₂DCFDA fluorescence and caused cell death. Interestingly, all processes occurred more slowly in moDCs than in monocytes. The mRNA profiler array showed more than 2-fold differential expression of 32 oxidative stress–related genes in unstimulated moDCs, including peroxiredoxin-2 (PRDX2), an enzyme reducing hydrogen peroxide and lipid peroxides. PRDX2 upregulation was confirmed by Taqman assays, immunoblotting and immunohistochemistry. Silencing PRDX2 in moDCs by means of siRNA significantly increased CM-DCF fluorescence and cell death upon tert-BHP-stimulation.

Conclusions

Our results indicate that moDCs exhibit higher intracellular antioxidant capacities, making them better equipped to resist oxidative stress than monocytes. Upregulation of PRDX2 is involved in the neutralization of ROS in moDCs. Taken together, this points to better survival skills of DCs in oxidative stress environments, such as atherosclerotic plaques.     

Identification of the chemokine CX3CL1 as a new regulator of malignant cell proliferation in epithelial ovarian cancer

Background

Little is known about the molecules that contribute to the growth of epithelial ovarian carcinomas (EOC), which remain the most lethal gynecological cancer in women. The chemokine Fractalkine/CX₃CL1 has been widely reported to play a biologically relevant role in tumor growth and spread. We report here the first investigation of the expression and role of CX₃CL1 in EOC.

Results

Epithelial cells from the surface of the ovary and the Fallopian tubes and from benign, borderline and malignant tumors all stained positive for CX₃CL1. In tumor specimens from 54 women who underwent surgical treatment for EOC diagnosis, CX₃CL1 immunoreactivity was unevenly distributed in epithelial tumor cells, and ranged from strong (33%) to absent (17%). This uneven distribution of CX₃CL1 did not reflect the morphological heterogeneity of EOC. It was positively correlated with the proliferation index Ki-67 and with GILZ (glucocorticoid-induced leucine zipper), previously identified as an activator of the proliferation of malignant EOC cells. Hierarchical clustering analysis, including age at diagnosis, tumor grade, FIGO stage, Ki-67 index, CX₃CL1, SDF-1/CXCL12 and GILZ immunostaining scores, distinguished two major clusters corresponding to low and high levels of proliferation and differing in terms of GILZ and CX₃CL1 expression. GILZ overexpression in the carcinoma-derived BG1 cell line resulted in parallel changes in CX₃CL1 products. Conversely, CX₃CL1 promoted through its binding to CX₃CR1 AKT activation and proliferation in BG1 cells. In a mouse subcutaneous xenograft model, the overexpression of GILZ was associated with higher expression of CX₃CL1 and faster tumor growth.

Conclusion

Our findings highlight the previously unappreciated constitutive expression of CX₃CL1 preceding tumorigenesis in ovarian epithelial cells. Together with GILZ, this chemokine emerges as a regulator of cell proliferation, which may be of potential clinical relevance for the selection of the most appropriate treatment for EOC patients.     

Assessing the role of CD103 in immunity to an intestinal helminth parasite

Background

In the intestine, the integrin CD103 is expressed on a subset of T regulatory (T_reg) cells and a population of dendritic cells (DCs) that produce retinoic acid and promote immune homeostasis. However, the role of CD103 during intestinal helminth infection has not been tested.

Methodology/Principal Findings

We demonstrate that CD103 is dispensable for the development of protective immunity to the helminth parasite Trichuris muris. While we observed an increase in the frequency of CD103⁺ DCs in the lamina propria (LP) following acute high-dose infection with Trichuris, lack of CD103 had no effect on the frequency of CD11c⁺ DCs in the LP or mesenteric lymph nodes (mLN). CD103-deficient (CD103^−/−) mice develop a slightly increased and earlier T cell response but resolve infection with similar kinetics to control mice. Similarly, low-dose chronic infection of CD103^−/− mice with Trichuris resulted in no significant difference in immunity or parasite burden. Absence of CD103 also had no effect on the frequency of CD4⁺CD25⁺Foxp3⁺ T_reg cells in the mLN or LP.

Conclusions/Significance

These results suggest that CD103 is dispensable for intestinal immunity during helminth infection. Furthermore, lack of CD103 had no effect on DC or T_reg recruitment or retention within the large intestine.     

CX3CR1 Is Expressed by Human B Lymphocytes and Meditates CX3CL1 Driven Chemotaxis of Tonsil Centrocytes

Background

Fractalkine/CX₃CL1, a surface chemokine, binds to CX₃CR1 expressed by different lymphocyte subsets. Since CX₃CL1 has been detected in the germinal centres of secondary lymphoid tissue, in this study we have investigated CX₃CR1 expression and function in human naïve, germinal centre and memory B cells isolated from tonsil or peripheral blood.

Methodology/Principal Findings

We demonstrate unambiguously that highly purified human B cells from tonsil and peripheral blood expressed CX₃CR1 at mRNA and protein levels as assessed by quantitative PCR, flow cytometry and competition binding assays. In particular, naïve, germinal centre and memory B cells expressed CX₃CR1 but only germinal centre B cells were attracted by soluble CX₃CL1 in a transwell assay. CX₃CL1 signalling in germinal centre B cells involved PI3K, Erk1/2, p38, and Src phosphorylation, as assessed by Western blot experiments. CX₃CR1⁺ germinal centre B cells were devoid of centroblasts and enriched for centrocytes that migrated to soluble CX₃CL1. ELISA assay showed that soluble CX₃CL1 was secreted constitutively by follicular dendritic cells and T follicular helper cells, two cell populations homing in the germinal centre light zone as centrocytes. At variance with that observed in humans, soluble CX₃CL1 did not attract spleen B cells from wild type mice. OVA immunized CX₃CR1⁻/⁻ or CX₃CL1⁻/⁻ mice showed significantly decreased specific IgG production compared to wild type mice.

Conclusion/Significance

We propose a model whereby human follicular dendritic cells and T follicular helper cells release in the light zone of germinal centre soluble CX₃CL1 that attracts centrocytes. The functional implications of these results warrant further investigation.     

Cross-Sectional Study on Attitudes among General Practitioners towards Pneumococcal Vaccination for Middle-Aged and Elderly Population in Hong Kong

Objective

To study the attitudes among general practitioners towards pneumococcal vaccination for middle-aged (50–64) and elderly population (over 65) in Hong Kong and the factors affecting their decision to advise pneumococcal vaccination for those age groups.

Design

Cross-sectional study of general practitioners in private practice in Hong Kong.

Participants

Members of Hong Kong Medical Association delivering general practice services in private sector.

Measuring Tool

Self-administered questionnaire.

Main Outcome Measures

Intention to recommend pneumococcal vaccination, barriers against pneumococcal vaccination.

Results

53.4% of the respondents would actively recommend pneumococcal vaccination to elderly patients but only 18.8% would recommend for middle-aged patients. Consultation not related to pneumococcal vaccine was the main reason for not recommending pneumococcal vaccine (43.6%). Rarity of pneumonia in their daily practice was another reason with 68.4% of respondents attending five or less patients with pneumonia each year. In multivariate analysis, factors such as respondents would get vaccination when reaching age 50 (OR_m 10.1), and attending 6 pneumonia cases or more per year (OR_m 2.28) were found to be associated with increasing likelihood for recommending vaccination to the middle-aged. While concerns of marketing a product (OR_m 0.41), consultation not related to vaccination (OR_m 0.45) and limited time (OR_m 0.38) were factors that reduced the likelihood.

Conclusion

Public policy is needed to increase the awareness of impact of pneumococcal pneumonia and the availability of preventive measures.     

FMS-related tyrosine kinase 3 ligand (Flt3L)/CD135 axis in rheumatoid arthritis

Introduction

The FMS-related tyrosine kinase 3 ligand (Flt3L)/CD135 axis plays a fundamental role in proliferation and differentiation of dendritic cells (DCs). As DCs play an important role in rheumatoid arthritis (RA) immunopathology we studied in detail the Flt3L/CD135 axis in RA patients.

Methods

The levels of Flt3L in (paired) serum and synovial fluid (SF) were quantified by enzyme-link immunosorbent assay (ELISA). Expression of Flt3L and CD135 in paired peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) was quantified by fluorescence-activated cell sorting (FACS). The expression of Flt3L, CD135 and TNF-Converting Enzyme (TACE) in synovial tissues (STs) and in vitro polarized macrophages and monocyte-derived DCs (Mo-DCs) was assessed by quantitative PCR (qPCR). CD135 ST expression was evaluated by immunohistochemistry and TACE ST expression was assessed by immunofluorescence. Flt3L serum levels were assessed in RA patients treated with oral prednisolone or adalimumab.

Results

Flt3L levels in RA serum, SF and ST were significantly elevated compared to gout patients and healthy individuals (HI). RA SF monocytes, natural killer cells and DCs expressed high levels of Flt3L and CD135 compared to HI. RA ST CD68⁺ and CD163⁺ macrophages, CD55⁺ fibroblast-like synoviocytes (FLS), CD31⁺ endothelial cells or infiltrating monocytes and CD19⁺ B cells co-expressed TACE. IFN-γ-differentiated macrophages expressed higher levels of Flt3L compared to other polarized macrophages. Importantly, Flt3L serum levels were reduced by effective therapy.

Conclusions

The Flt3L/CD135 axis is active in RA patients and is responsive to both prednisolone and adalimumab treatment. Conceivably, this ligand receptor pair represents a novel therapeutic target.     

Association of Body Mass Index with All-Cause and Cardiovascular Disease Mortality in the Elderly

Objectives

To evaluate the associations of body mass index (BMI) with all-cause, cardiovascular disease (CVD), and expanded CVD mortality in the elderly.

Design

Observational cohort study.

Setting

Annual physical examination program for the elderly from 2006 to 2010.

Participants

We included 77,541 Taipei residents aged ≥65 years (39,365 men and 38,176 women).

Measurements

BMI was categorized as underweight (BMI<18.5), normal weight (18.5≤BMI<25), overweight (25≤BMI<30), grade 1 obesity (30≤BMI<35), or grade 2–3 obesity (BMI≥35). Mortality was ascertained by national death files.

Results

Underweight (hazard ratios [HRs] of all-cause, CVD, and expanded CVD mortality: 1.92, 1.74, and 1.77, respectively), grade 2–3 obesity (HRs: 1.59, 2.36, and 2.22, respectively), older age, male sex, smoking, and high fasting blood sugar were significant predictors of mortality. Meanwhile, being married/cohabitating, higher education, alcohol consumption, more regular exercise, and high total cholesterol were inversely associated with mortality. Multivariate stratified subgroup analyses verified smokers (HRs of all-cause, CVD, and expanded CVD mortality: 3.25, 10.71, and 7.86, respectively, for grade 2–3 obesity), the high triglyceride group (HRs: 5.82, 10.99, and 14.22, respectively for underweight), and patients with 3–4 factors related to metabolic syndrome (HRs: 4.86, 12.72, and 11.42, respectively, for underweight) were associated with mortality.

Conclusion

The associations of BMI with all-cause, CVD, expanded CVD mortality in the elderly are represented by U-shaped curves, suggesting unilateral promotions or interventions in weight reduction in the elderly may be inappropriate. Heterogeneous effects of grades 1 and 2–3 obesity on mortality were observed and should be treated as different levels of obesity.     

Assessment of health status in elderly patients with cancer

Background

Health status assessment of senior adults is one of the most important aspects of a treatment decision making process. A group of elderly cancer patients is very heterogeneous according to the health status – some of them are fit enough for aggressive treatment, but others are frail and vulnerable. Treatment for the latter group has to be adapted and carefully monitored.

Aim

To review and analyze relevant literature on the usage and optimization of Comprehensive Geriatric Assessment (CGA).

Materials and methods

Medline search of studies published between 2000 and 2011, containing key words: Comprehensive Geriatric Assessment, aging, cancer in senior adults, frailty.

Results

To recognize and address individual needs of senior adults, a special holistic approach has been developed – comprehensive geriatric assessment (CGA). This tool is a gold standard in gerontooncology, recommended by International Society of Geriatric Oncology. CGA evaluates all important health domains, from physiology to social and economical problems, using sets of different tests. Assessment has to be performed by a trained team, including a physician, nurse and social worker. CGA has been clinically validated in many studies, but it is still not clear whether CGA improves the outcome of treatment of the elderly with cancer.

Conclusions

Complexity and multidimensionality of CGA pose a logistic challenge for everyday clinical practice. Special senior programs, which could be developed inside comprehensive cancer center, focusing attention on seniors’ problems and needs seem to be a way forward for geriatric oncology.     

HMGB1-dependent triggering of HIV-1 replication and persistence in dendritic cells as a consequence of NK-DC cross-talk

Background

HIV-1 has evolved ways to exploit DCs, thereby facilitating viral dissemination and allowing evasion of antiviral immunity. Recently, the fate of DCs has been found to be extremely dependent on the interaction with autologous NK cells, but the mechanisms by which NK-DC interaction controls viral infections remain unclear. Here, we investigate the impact of NK-DC cross-talk on maturation and functions of HIV-infected immature DCs.

Methodology/Principal Findings

Immature DCs were derived from primary monocytes, cultured in the presence of IL-4 and GM-CSF. In some experiments, DCs were infected with R5-HIV-1_BaL or X4-HIV-1_NDK, and viral replication, proviral HIV-DNA and the frequency of infected DCs were measured. Autologous NK cells were sorted and either kept unstimulated in the presence of suboptimal concentration of IL-2, or activated by a combination of PHA and IL-2. The impact of 24 h NK-DC cross-talk on the fate of HIV-1-infected DCs was analyzed. We report that activated NK cells were required for the induction of maturation of DCs, whether uninfected or HIV-1-infected, and this process involved HMGB1. However, the cross-talk between HIV-1-infected DCs and activated NK cells was functionally defective, as demonstrated by the strong impairment of DCs to induce Th1 polarization of naïve CD4 T cells. This was associated with the defective production of IL-12 and IL-18 by infected DCs. Moreover, the crosstalk between activated NK cells and HIV-infected DCs resulted in a dramatic increase in viral replication and proviral DNA expression in DCs. HMGB1, produced both by NK cells and DCs, was found to play a pivotal role in this process, and inhibition of HMGB1 activity by glycyrrhizin, known to bind specifically to HMGB1, or blocking anti-HMGB1 antibodies, abrogated NK-dependent HIV-1 replication in DCs.

Conclusion

These observations provide evidence for the crucial role of NK-DC cross-talk in promoting viral dissemination, and challenge the question of the in vivo involvement of HMGB1 in the triggering of HIV-1 replication and replenishment of viral reservoirs in AIDS.     

Relevance of Distinct Monocyte Subsets to Clinical Course of Ischemic Stroke Patients

Background and Purpose

The most common strategy for treating patients with acute ischemic stroke is thrombolytic therapy, though only a few patients receive benefits because of the narrow time window. Inflammation occurring in the central nervous system (CNS) in association with ischemia is caused by immune cells including monocytes and involved in lesion expansion. If the specific roles of monocyte subsets in stroke can be revealed, they may become an effective target for new treatment strategies.

Methods

We performed immunological examinations of 36 consecutive ischemic stroke patients within 2 days of onset and compared the results with 24 age-matched patients with degenerative disorders. The stroke patients were repeatedly tested for the proportions of monocyte subsets in blood, and serum levels of pro- and anti-inflammatory cytokines immediately after admission, on days 3-7 and 12-16 after stroke onset, and on the day of discharge. In addition, immunological measurements were analyzed for relationships to stroke subtypes and complications, including progressive infarction (PI) and stroke-associated infection (SAI).

Results

Monocyte count was significantly increased from 0–16 days after stroke as compared to the controls (p<0.05). CD14^highCD16^- classical and CD14^highCD16⁺ intermediate monocytes were significantly increased from 0-7 and 3-16 days after stroke, respectively (p<0.05), whereas CD14 ^dimCD16^high non-classical monocytes were decreased from 0–7 days (p<0.05). Cardioembolic infarction was associated with a persistent increase in intermediate monocytes. Furthermore, intermediate monocytes were significantly increased in patients with PI (p<0.05), while non-classical monocytes were decreased in those with SAI (p<0.05). IL-17A levels were positively correlated with monocyte count (r=0.485, p=0.012) as well as the percentage of non-classical monocytes (r=0.423, p=0.028), and negatively with that of classical monocytes (r=-0.51, p=0.007) during days 12-16.

Conclusions

Our findings suggest that CD14^highCD16⁺ intermediate monocytes have a role in CNS tissue damage during acute and subacute phases in ischemic stroke especially in relation to cardioembolism.     

Age-Related Modifications to the Magnitude and Periodicity of Neuromuscular Noise

Background

Evaluation of task related outcomes within geriatric and fall-prone populations is essential not only for identification of neuromuscular deficits, but also for effective implementation of fall prevention strategies. As most tasks and activities of daily living are performed at submaximal force levels, restoration of muscle strength often does not produce the expected benefit in functional capacity. However, it is known that muscular control plays a key role in the performance of functional tasks, but it remains unclear to what degree muscular control and the associated neuromuscular noise (NmN) is age-related, particularly in the lower-extremities.

Objectives

The aim of this study was to determine the effects of age and fall-pathology on the magnitude as well as the frequency of NmN during lower extremity force production.

Methods

Sixteen young healthy adults, as well as seventy elderly women (36 healthy, 34 elderly fallers), performed force production tests at moderate levels (15% of maximum voluntary isometric contractions).

Results

Elderly fallers exhibited the highest magnitude of NmN, while the highest frequency components of NmN tended to occur in the healthy elderly. Young subjects exhibited significantly more power in the low frequency ranges than either of the elderly groups, and had the lowest levels of NmN.

Conclusion

These data suggest increased degeneration of muscular control through greater NmN in elderly fallers compared to healthy elderly or young subjects. This could possibly be associated with muscle atrophy and lower levels of motor unit synchronisation.     

Elevated Atherosclerosis-Related Gene Expression,Monocyte Activation and Microparticle-Release Are Related to Increased Lipoprotein-Associated Oxidative Stress in Familial Hypercholesterolemia

Objective

Animal and in vitro studies have suggested that hypercholesterolemia and increased oxidative stress predisposes to monocyte activation and enhanced accumulation of oxidized LDL cholesterol (oxLDL-C) through a CD36-dependent mechanism. The aim of this study was to investigate the hypothesis that elevated oxLDL-C induce proinflammatory monocytes and increased release of monocyte-derived microparticles (MMPs), as well as up-regulation of CD36, chemokine receptors and proinflammatory factors through CD36-dependent pathways and that this is associated with accelerated atherosclerosis in subjects with heterozygous familial hypercholesterolemia (FH), in particular in the presence of Achilles tendon xanthomas (ATX).

Approach and Results

We studied thirty FH subjects with and without ATX and twenty-three healthy control subjects. Intima-media thickness (IMT) and Achilles tendon (AT) thickness were measured by ultrasonography. Monocyte classification and MMP analysis were performed by flow cytometry. Monocyte expression of genes involved in atherosclerosis was determined by quantitative PCR. IMT and oxLDL-C were increased in FH subjects, especially in the presence of ATX. In addition, FH subjects had elevated proportions of intermediate CD14++CD16+ monocytes and higher circulating MMP levels. Stepwise linear regression identified oxLDL-C, gender and intermediate monocytes as predictors of MMPs. Monocyte expression of pro-atherogenic and pro-inflammatory genes regulated by oxLDL-C-CD36 interaction was increased in FH, especially in ATX+ subjects. Monocyte chemokine receptor CX₃CR1 was identified as an independent contributor to IMT.

Conclusions

Our data support that lipoprotein-associated oxidative stress is involved in accelerated atherosclerosis in FH, particularly in the presence of ATX, by inducing pro-inflammatory monocytes and increased release of MMPs along with elevated monocyte expression of oxLDL-C-induced atherosclerosis-related genes.     

Different capacity of monocyte subsets to phagocytose iron-oxide nanoparticles

Objective

To explore the capacity of human CD14⁺CD16⁺⁺ and CD14⁺⁺CD16^- monocytes to phagocyte iron-oxide nanoparticles in vitro.

Methods

Human monocytes were labeled with four different magnetic nanoparticle preparations (Ferumoxides, SHU 555C, CLIO-680, MION-48) exhibiting distinct properties and cellular uptake was quantitatively assessed by flow cytometry, fluorescence microscopy, atomic absorption spectrometry and Magnetic Resonance Imaging (MRI). Additionally we determined whether cellular uptake of the nanoparticles resulted in phenotypic changes of cell surface markers.

Results

Cellular uptake differed between the four nanoparticle preparations. However for each nanoparticle tested, CD14⁺⁺CD16^- monocytes displayed a significantly higher uptake compared to CD14⁺CD16⁺⁺ monocytes, this resulted in significantly lower T1 and T2 relaxation times of these cells. The uptake of iron-oxide nanoparticles further resulted in a remarkable shift of expression of cell surface proteins indicating that the labeling procedure affects the phenotype of CD14⁺CD16⁺⁺ and CD14⁺⁺CD16^- monocytes differently.

Conclusion

Human monocyte subsets internalize different magnetic nanoparticle preparations differently, resulting in variable loading capacities, imaging phenotypes and likely biological properties.     

Sex Differences in Monocyte Activation in Systemic Lupus Erythematosus (SLE)

Introduction

TLR7/8 and TLR9 signaling pathways have been extensively studied in systemic lupus erythematosus (SLE) as possible mediators of disease. Monocytes are a major source of pro-inflammatory cytokines and are understudied in SLE. In the current project, we investigated sex differences in monocyte activation and its implications in SLE disease pathogenesis.

Methods

Human blood samples from 27 healthy male controls, 32 healthy female controls, and 25 female patients with SLE matched for age and race were studied. Monocyte activation was tested by flow cytometry and ELISA, including subset proportions, CD14, CD80 and CD86 expression, the percentage of IL-6-producing monocytes, plasma levels of sCD14 and IL-6, and urine levels of creatinine.

Results

Monocytes were significantly more activated in women compared to men and in patients with SLE compared to controls in vivo. We observed increased proportions of non-classic monocytes, decreased proportions of classic monocytes, elevated levels of plasma sCD14 as well as reduced surface expression of CD14 on monocytes comparing women to men and lupus patients to controls. Plasma levels of IL-6 were positively related to sCD14 and serum creatinine.

Conclusion

Monocyte activation and TLR4 responsiveness are altered in women compared to men and in patients with SLE compared to controls. These sex differences may allow persistent systemic inflammation and resultant enhanced SLE susceptibility.