Pneumococcal vaccination may induce anti-oxidized low-density lipoprotein antibodies that have potentially protective effects against cardiovascular disease

Impact of influenza, herpes zoster, and pneumococcal vaccinations on the incidence of cardiovascular events in subjects aged over 65 years: a systematic review

This systematic review aims to summarize the impact of vaccination against influenza, shingles, and pneumococcus on the incidence on the risk of cardiovascular events in the elderly. This protocol was developed in accordance with PRISMA guidelines. We conducted a literature search and identified all relevant articles published regarding the matter up to September 2022. We retrieved 38 studies (influenza vaccine = 33, pneumococcal vaccine = 5, and zoster vaccine = 2). A total of 28 and 2 studies have shown that influenza and pneumococcal vaccines significantly lower the risk of cardiovascular disease in the elderly. Also, repeated influenza vaccination shows a consistent and dose-dependent protective effect against acute coronary syndromes and stroke. Moreover, dual influenza and pneumococcal vaccination was associated with lower risks of some cardiovascular events (stroke, congestive heart failure, ischemic heart disease, and myocardial infarction). However, the impact of PCV13 on cardiovascular events has not been studied, nor has the currently recommended vaccination schedule (PCV13 + PPV23). As for herpes zoster vaccination, only the protective effect against stroke has been studied with the live attenuated herpes zoster vaccine, but no studies have been conducted with the recombinant subunit herpes zoster vaccine. This review outlines the benefits of the vaccines mentioned above beyond their preventive action on infectious diseases. It is intended for health professionals who wish to inform and advise their elderly patients.

23-valent pneumococcal polysaccharide vaccine and the risk of renal progression in older patients with chronic kidney disease

BACKGROUND

The 23-valent pneumococcal polysaccharide vaccine (PPSV23) ensures favorable outcomes and reduces the risk of cardiac events in patients on dialysis. However, the effect of PPSV23 vaccination on renal function remains unknown, particularly in patients with chronic kidney disease (CKD). Therefore, we investigated the association between PPSV23 efficacy and renal progression in older patients (age ≥ 75 years) with CKD.

METHODS

This multicenter, longitudinal cohort study was conducted using data (2008-2016) from the Epidemiology and Risk Factors Surveillance of CKD database. This database was associated with Taiwan's National Health Insurance Research Database (for period: 2008-2019). A total of 1195 older patients with CKD were recruited from 14 hospitals and communities across Taiwan. Renal progression was defined as a > 25% reduction in estimated glomerular filtration rate from the baseline value.

RESULTS

A significant reduction in the risk of renal progression was observed in patients who had received PPSV23 (adjusted hazard ratio [HR]: 0.57; 95% confidence interval [CI]: 0.35-0.91). However, when stratified by CKD stage, this significant reduction was observed in patients with early-stage CKD but not in those with late-stage CKD. Furthermore, a significant reduction in the risk of renal progression was noted in male patients and those with hypertension.

CONCLUSION

Our findings support the protective effect of PPSV23 against renal deterioration in older patients with CKD.

Persistence of Detectable Anti-Pneumococcal Antibodies 4 Years After Pneumococcal Polysaccharide Vaccination in a Randomised Controlled Trial: The Australian Study for the Prevention through Immunisation of Cardiovascular Events (AUSPICE)

AIM

Mouse models have indicated that the pneumococcal polysaccharide vaccine (PPV) can reduce atherosclerosis. This is probably through a process of molecular mimicry, where phosphorylcholine in the capsular polysaccharide of the vaccine elicits antibodies that cross-react with oxidised low-density lipoprotein and reduce plaque. We investigated whether a similar mechanism occurs in humans.

METHODS

A large national blinded, randomised, placebo-controlled trial of the PPV (Australian Study for the Prevention through Immunisation of Cardiovascular Events [AUSPICE]) is underway with fatal and nonfatal cardiovascular disease (CVD) events as the primary outcome. Participants at one centre agreed to a substudy measuring a number of biomarkers and surrogates of CVD over 4 years, including anti-pneumococcal antibodies (immunoglobulin G and immunoglobulin M), C-reactive protein, carotid intima-media thickness, pulse wave velocity, insulin, fasting blood glucose, glycated haemoglobin, and hepatorenal index.

RESULTS

Antipneumococcal immunoglobulin G and immunoglobulin M were both present and statistically significantly increased in the treated group compared to control at 4 years. However, there were no differences in any of the surrogate measures of CVD or metabolic markers at 4 years.

CONCLUSIONS

While there were prolonged differences in anti-pneumococcal antibody titres following PPV vaccination, these did not appear to provide any cardioprotective effect, as measured by a range of markers. Final results using the fatal and nonfatal CVD events await the completion of national health record linkage next year.

TRIAL REGISTRATION

ACTRN12615000536561.

Generation of cardio-protective antibodies after pneumococcal polysaccharide vaccine: Early results from a randomised controlled trial

BACKGROUND AND AIMS

Observational studies have demonstrated that the pneumococcal polysaccharide vaccine (PPV) is associated with reduced risk of cardiovascular events. This may be mediated through IgM antibodies to OxLDL, which have previously been associated with cardioprotective effects. The Australian Study for the Prevention through Immunisation of Cardiovascular Events (AUSPICE) is a double-blind, randomised controlled trial (RCT) of PPV in preventing ischaemic events. Participants received PPV or placebo once at baseline and are being followed-up for incident fatal and non-fatal myocardial infarction or stroke over 6 years.

METHODS

A subgroup of participants at one centre (Canberra; n = 1,001) were evaluated at 1 month and 2 years post immunisation for changes in surrogate markers of atherosclerosis, as pre-specified secondary outcomes: high-sensitive C-reactive protein (CRP), pulse wave velocity (PWV), and carotid intima-media thickness (CIMT). In addition, 100 participants were randomly selected in each of the intervention and control groups for measurement of anti-pneumococcal antibodies (IgG, IgG2, IgM) as well as anti-OxLDL antibodies (IgG and IgM to CuOxLDL, MDA-LDL, and PC-KLH).

RESULTS

Concentrations of anti-pneumococcal IgG and IgG2 increased and remained high at 2 years in the PPV group compared to the placebo group, while IgM increased and then declined, but remained detectable, at 2 years. There were statistically significant increases in all anti-OxLDL IgM antibodies at 1 month, which were no longer detectable at 2 years; there was no increase in anti-OxLDL IgG antibodies. There were no significant changes in CRP, PWV or CIMT between the treatment groups at the 2-year follow-up.

CONCLUSIONS

PPV engenders a long-lasting increase in anti-pneumococcal IgG, and to a lesser extent, IgM titres, as well as a transient increase in anti-OxLDL IgM antibodies. However, there were no detectable changes in surrogate markers of atherosclerosis at the 2-year follow-up. Long-term, prospective follow-up of clinical outcomes is continuing to assess if PPV reduces CVD events.

How Children Are Protected From COVID-19? A Historical, Clinical, and Pathophysiological Approach to Address COVID-19 Susceptibility

The origin and the global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) in early 2020 was accompanied by high rates of mortality in regions belonging to the ancient silk road, such as the south of China, Iran, Turkey and the northern parts of Italy. However, children seem to be spared in the epidemic as very small percentage worldwide being ill. The protection of children and neonates suggests the involvement of a specific component of adaptive immunity present at early development. Native immunoglobulin belonging to the class of IgM is abundantly present in neonates and children and is known for its recognition of self- and altered self-antigens. Native IgM may be able to neutralize virus by the recognition of endogenous "danger signal" encoded in the viral envelope and originally imprinted in the membranes of infected and stressed cells. Noteworthy, thrombosis and vasculitis, two symptoms in severely affected adult and pediatric patients are shared between COVID-19 and patients with Behcet's disease, an autoimmune disorder exhibiting a region-specific prevalence in countries of the former silk road. Molecular mechanisms and clinical indicators suggest reactive oxygen species as trigger factor for severe progression of COVID-19 and establish a link to the innate immune defense against bacteria. The selective pressure exerted by bacterial pathogens may have shaped the genetics of inhabitants at this ancient trade route in favor of bacterial defense, to the detriment of severe COVID-19 progression in the 21th century.

Pneumococcal polysaccharide vaccine is a cost saving strategy for prevention of acute coronary syndrome

OBJECTIVE

There is evidence that the pneumococcal polysaccharide vaccine (PPV) may reduce cardiovascular disease. We aimed to evaluate the cost-effectiveness of PPV for primary prevention of acute coronary syndrome (ACS) in the elderly in Australia.

METHODS

A Markov model was developed to investigate the costs, QALYs and ICERs of PPV administration in those aged ≥65 years without a history of ACS from the perspective of Australian healthcare system, using elderly-specific clinical data and local costs from Australian Heart Foundation and Australian Institute of Health and Welfare databases. A ten-years horizon was used, and all costs and health outcomes were discounted at 5% annually. The impact of various assumptions was tested with sensitivity analyses.

RESULTS

In the base-case analysis, interventional strategy (100% PPV coverage) prevented an additional five incident ACS events among 1000 "healthy" elderly individuals compared with standard of care (50% PPV coverage) over 10 years. 100% PPV was the dominant strategy, resulting in a QALY gain of 0.0075 and cost saving of AU$ 179 per person. The results were most sensitive to effectiveness of PPV at preventing ACS and reducing hospital bed-days, and cost of ACS admission, but in all sensitivity analyses 100% PPV remained the dominant strategy. Shortening the time horizon from ten to five years resulted in further cost saving.

CONCLUSION

PPV for the prevention of ACS in those aged ≥65 is a dominant intervention strategy, with cost saving and minor improvements in QALY. Healthcare providers should promote PPV administration for all eligible populations.

ApoB-Specific CD4+ T Cells in Mouse and Human Atherosclerosis

Atherosclerosis is a chronic inflammatory condition of the arterial wall that leads to the formation of vessel-occluding plaques within the subintimal space of middle-sized and larger arteries. While traditionally understood as a myeloid-driven lipid-storage disease, growing evidence suggests that the accumulation of low-density lipoprotein cholesterol (LDL-C) ignites an autoimmune response with CD4⁺ T-helper (T_H) cells that recognize self-peptides from Apolipoprotein B (ApoB), the core protein of LDL-C. These autoreactive CD4⁺ T cells home to the atherosclerotic plaque, clonally expand, instruct other cells in the plaque, and induce clinical plaque instability. Recent developments in detecting antigen-specific cells at the single cell level have demonstrated that ApoB-reactive CD4⁺ T cells exist in humans and mice. Their phenotypes and functions deviate from classical immunological concepts of distinct and terminally differentiated T_H immunity. Instead, ApoB-specific CD4⁺ T cells have a highly plastic phenotype, can acquire several, partially opposing and mixed transcriptional programs simultaneously, and transit from one T_H subset into another over time. In this review, we highlight adaptive immune mechanisms in atherosclerosis with a focus on CD4⁺ T cells, introduce novel technologies to detect ApoB-specific CD4⁺ T cells at the single cell level, and discuss the potential impact of ApoB-driven autoimmunity in atherosclerosis.

The Effect of a 13-Valent Conjugate Pneumococcal Vaccine on Circulating Antibodies Against Oxidized LDL and Phosphorylcholine in Man, A Randomized Placebo-Controlled Clinical Trial

Simple Summary

Atherosclerosis is the main underlying mechanism for cardiovascular disease. The main cause for atherosclerosis development is oxidized low density lipoprotein (oxLDL) accumulation in the vessel wall and a subsequent immune response. It has been established that immunoglobulin M antibodies against oxLDL help protect against atherosclerosis. It has been found in mice that vaccination with Streptococcus pneumoniae results in an increase of these protective antibodies and thereby decreases the development of atherosclerosis. In this study, we investigated if this increase of antibodies can be found in human as well. Twenty-four healthy male volunteers were vaccinated with Prevenar-13, a pneumococcal vaccine, using different dosing regimens. An increase in anti-Prevenar antibodies was found, showing that the vaccination worked. However, no increase in protective anti-phosphorylcholine or anti-oxLDL antibodies was observed. This work shows that vaccination against pneumococcal does not seem to be a suitable treatment option to help prevent atherosclerosis development, although further research would be required to test alternative pneumococcal-based vaccines, vaccination regimens or study populations.

Abstract

In mice vaccination with Streptococcus pneumoniae results in an increase in anti-oxLDL IgM antibodies due to mimicry of anti-phosphorylcholine (present in the cell wall of S. pneumoniae) and anti-oxLDL IgM. In this study we investigated the human translation of this molecular mimicry by vaccination against S. pneumoniae using the Prevenar-13 vaccine. Twenty-four healthy male volunteers were vaccinated with Prevenar-13, either three times, twice or once in a double-blind, placebo-controlled, randomized single center clinical study. Anti-pneumococcal wall, oxLDL and phosphorycholine antibody levels were measured at a fixed serum dilution, as well as circulating lipid levels over the course of 68 weeks. A significant increase in anti-oxLDL IgG and IgM was seen in the group receiving two doses six months apart compared to the placebo. However, these differences were not observed in the groups receiving a single dose, two doses one month apart, or three doses. This study shows that vaccination with Prevenar-13 does not result in robust anti-oxLDL IgM levels in humans. Further research would be required to test alternative pneumococcal-based vaccines, vaccination regimens or study populations, such as cardiovascular disease patients.

Safety and Efficacy of Simultaneous Inoculations of Pneumococcal and Influenza Vaccines in Patients with Coronary Artery Disease

Aim: Pneumococcal and influenza infections can cause serious morbidity and mortality in patients with cardiovascular diseases. The purpose of this study was to investigate the safety and efficacy of simultaneous inoculations of 23-valent pneumococcal polysaccharide vaccine (PPSV23) and trivalent influenza vaccine (TIV) in patients with coronary artery disease (CAD).

Methods: This was a prospective, randomized, single-blind, placebo-controlled study. A total of 40 patients with CAD were randomly assigned to the TIV＋PPSV23 (simultaneous inoculations of TIV and PPSV23) and TIV＋Placebo (inoculations of TIV and placebo) groups. Primary outcomes were the safety of simultaneous vaccinations and the changing of circulating cardiovascular biomarkers before, at 4-, and at 12-weeks after vaccinations.

Results: The baseline characteristics between the two groups were identical. The prevalence of injection-site pain, swelling, and reddening were 47%, 37%, and 37% in the TIV＋PPSV23 group, and 10%, 5%, and 0% in the TIV＋Placebo group, respectively. All reactions were self-limited. Body temperature ＞37.0℃ or serious injection-related reaction was not observed. The levels of white blood cells, high-sensitivity C-reactive protein, N-terminal pro-B-type natriuretic peptide, pentraxin-3, and malondialdehide-modified low-density lipoprotein (LDL), were not significantly different between the two groups before and after vaccinations. The levels of anti-oxidized LDL were significantly and step-wisely decreased from baseline, to 4-, and 12-weeks vaccinations in the both groups. No significant changes of other markers were observed in both groups at each time point.

Conclusion: Simultaneous inoculations of TIV and PPSV23 were safety in patients with CAD, suggesting that dual vaccinations can be considered even in patients with CAD.

23-valent pneumococcal polysaccharide vaccine improves survival in dialysis patients by preventing cardiac events

BACKGROUND

Immunodeficient patients are recommended to receive pneumococcal vaccination. However, there is limited evidence showing effectiveness of the polysaccharide vaccine. Polysaccharide vaccination has shown an association with cardiovascular event risk reduction. We assessed the efficacy of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in relation to the risk of hospitalization and death due to pneumonia and acute cardiac events.

METHODS

The medical records of all dialysis patients attending our 8 study centers in 2010 were studied, and we selected 1038 consecutive patients. One-to-one propensity score matching was used to correct for potential selection bias in a PPSV23-vaccinated group versus a non-vaccinated group, and a total of 510 patients were identified for outcome analysis. Time to first admission, or deaths due to all-cause pneumonia or cardiac events until 2015 were compared between both groups.

RESULTS

The all-cause death rate was significantly decreased in the PPSV23-vaccinated group, (hazard ratio [HR] 0.62, 95% confidence interval [CI]; 0.46-0.83, P = 0.002). All-cause death was considered to be a competing risk for the other outcomes. Further outcomes were evaluated by competing risk analysis adjusting for mortality. There was no statistically significant difference in the hospitalization rate for pneumonia; however, the hospitalization rate due to cardiac events was significantly lower in the PPSV23-vaccinated group than in the non-vaccinated group (HR 0.44, 95% CI; 0.20-0.96, P = 0.040). There was no statistically significant difference in the death rate due to pneumonia; however, the rate of cardiac death was significantly lower in the PPSV23-vaccinated group than in the non-vaccinated group (HR 0.36, 95% CI; 0.18-0.71, P = 0.003).

CONCLUSIONS

The PPSV23 vaccination is associated with a good prognosis and a low-risk of cardiac events in dialysis patients; however, there was no evidence indicating enhanced protective efficacy against pneumonia, suggesting the PPSV23 vaccination might improve the prognosis by directly preventing cardiovascular events.

IgM Natural Autoantibodies in Physiology and the Treatment of Disease

Antibodies are vital components of the adaptive immune system for the recognition and response to foreign antigens. However, some antibodies recognize self-antigens in healthy individuals. These autoreactive antibodies may modulate innate immune functions. IgM natural autoantibodies (IgM-NAAs) are a class of primarily polyreactive immunoglobulins encoded by germline V-gene segments which exhibit low affinity but broad specificity to both foreign and self-antigens. Historically, these autoantibodies were closely associated with autoimmune disease. Nevertheless, not all human autoantibodies are pathogenic and compelling evidence indicates that IgM-NAAs may exert a spectrum of effects from injurious to protective depending upon cellular and molecular context. In this chapter, we review the current state of knowledge regarding the potential physiological and therapeutic roles of IgM-NAAs in different disease conditions such as atherosclerosis, cancer, and autoimmune disease. We also describe the discovery of two reparative IgM-NAAs by our laboratory and delineate their proposed mechanisms of action in central nervous system (CNS) disease.

Rationale and design of a randomized controlled trial of pneumococcal polysaccharide vaccine for prevention of cardiovascular events: The Australian Study for the Prevention through Immunization of Cardiovascular Events (AUSPICE)

BACKGROUND

Research has shown that vaccination with Streptococcus pneumoniae reduced the extent of atherosclerosis in experimental animal models. It is thought that phosphorylcholine lipid antigens in the S. pneumoniae cell wall induce the production of antibodies that cross-react with oxidized low-density lipoprotein, a component of atherosclerotic plaques. These antibodies may bind to and facilitate the regression of the plaques. Available data provide evidence that similar mechanisms also occur in humans, leading to the possibility that pneumococcal vaccination protects against atherosclerosis. A systematic review and meta-analysis, including 8 observational human studies, of adult pneumococcal polysaccharide vaccination for preventing cardiovascular disease in people older than 65 years, showed a 17% reduction in the odds (odds ratio 0.83, 95% CI 0.71-0.97) of having an acute coronary syndrome event.

METHODS/DESIGN

The AUSPICE is a multicenter, randomized, placebo-controlled, double-blind, clinical trial to formally test whether vaccination with the pneumococcal polysaccharide vaccine protects against cardiovascular events (fatal and nonfatal acute coronary syndromes and ischemic strokes). Cardiovascular outcomes will be obtained during 4 to 5 years of follow-up, through health record linkage with state and national administrative data sets.

CONCLUSION

This is the first registered randomized controlled trial (on US, World Health Organization, Australia and New Zealand trial registries) to be conducted to test whether vaccination with the pneumococcal polysaccharide vaccine will reduce cardiovascular events. If successful, vaccination can be readily extended to at-risk groups to reduce the risk of cardiovascular diseases.

Higher risk for incident heart failure and cardiovascular mortality among community-dwelling octogenarians without pneumococcal vaccination

AIMS

Octogenarians have the highest incidence of heart failure (HF) that is not fully explained by traditional risk factors. We explored whether lack of pneumococcal vaccination is associated with higher risk of incident HF among octogenarians.

METHODS AND RESULTS

In the Cardiovascular Health Study (CHS), 5290 community-dwelling adults, ≥65 years of age, were free of baseline HF and had data on pneumococcal vaccination. Of these, 851 were octogenarians, of whom, 593 did not receive pneumococcal vaccination. Multivariable-adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for associations of lack of pneumococcal vaccination with incident HF and other outcomes during 13 years of follow-up were estimated using Cox regression models, adjusting for demographics and other HF risk factors including influenza vaccination. Octogenarians had a mean (±SD) age of 83 (±3) years; 52% were women and 17% African American. Overall, 258 participants developed HF and 662 died. Lack of pneumococcal vaccination was associated with higher relative risk of incident HF (aHR, 1.37; 95% CI, 1.01-1.85; P = 0.044). There was also higher risk for all-cause mortality (aHR, 1.23; 95% CI, 1.02-1.49; P = 0.028), which was mostly driven by cardiovascular mortality (aHR, 1.45; 95% CI, 1.06-1.98; P = 0.019). Octogenarians without pneumococcal vaccination had a trend toward higher risk of hospitalization due to pneumonia (aHR, 1.34; 95% CI, 0.99-1.81; P = 0.059). These associations were not observed among those 65-79 years of age.

CONCLUSIONS

Among community-dwelling octogenarians, lack of pneumococcal vaccination was associated with a significantly higher independent risk of incident HF and mortality, and trend for higher pneumonia hospitalization.

Effect of the adult pneumococcal polysaccharide vaccine on cardiovascular disease: a systematic review and meta-analysis

Animal models and clinical studies suggest a mechanistic link between the pneumococcal polysaccharide vaccine (PPV) and a cardiovascular protective effect. However, conflicting results exist from several large observational studies in humans. We set out to systematically review current literature and conduct meta-analyses of studies on PPV and cardiovascular outcomes. Medline, Embase and CENTRAL were searched for randomised controlled trials (RCTs) and observational studies in adults, using PPV as the intervention, up to 30 April 2014. Studies that compared PPV with a control (another vaccine, no vaccine or placebo) and recorded ischaemic events were included in this review. Two investigators extracted data independently on study design, baseline characteristics and summary outcomes. Study quality was examined using the Newcastle-Ottawa Quality Assessment Scale. Pooled estimates using random effects models and their 95% CIs were calculated separately for the outcomes of acute coronary syndrome (ACS) events and stroke. No RCT data were available. A total of 230 426 patients were included in eight observational studies and recorded as ACS events. PPV was associated with significantly lower odds of ACS events in patients 65 years and older (pooled OR=0.83 (95% CI 0.71 to 0.97), I(2)=77.0%). However, there was no significant difference in ACS events when younger people were included (pooled OR=0.86 (95% CI 0.73 to 1.01), I(2)=81.4%). Pooling of four studies, covering a total of 192 210 patients, did not find a significantly reduced risk of stroke in all patients (pooled OR=1.00 (95% CI 0.89 to 1.12), I(2)=55.3%), or when restricted to those 65 years and older (pooled OR=0.96 (95% CI 0.87 to 1.05), I(2)=22.5%). In this meta-analysis of observational studies, the use of PPV was associated with a significantly lower risk of ACS events in the older population, but not stroke. An adequately powered and blinded RCT to confirm these findings is warranted.

Targeting the adaptive immune system: new strategies in the treatment of atherosclerosis

Atherosclerosis is a lipid-driven chronic inflammatory disease of the arterial wall. Current treatment of atherosclerosis is focused on limiting its risk factors, such as hyperlipidemia or hypertension. However, treatments that target the inflammatory nature of atherosclerosis are still under development. Discovery of novel targets involved in the inflammation of the arterial wall creates opportunities to design new therapeutics that successfully modulate atherosclerosis. Here, we review drug targets that have proven to play pivotal roles in the adaptive immune system in atherosclerosis, and we discuss their potential as novel therapeutics.

Immunization with advanced glycation end products modified low density lipoprotein inhibits atherosclerosis progression in diabetic apoE and LDLR null mice

Background

Diabetes accelerates atherosclerosis through undefined molecular mechanisms. Hyperglycemia induces formation of advanced glycation end product (AGE)-modified low-density lipoprotein (LDL). Anti-AGE-LDL autoantibodies favor atherosclerosis (AS) progression in humans, while anti oxidized LDL immunization inhibits AS in hypercholesterolemic, non-diabetic mice. We here investigated if AGE-LDL immunization protects against AS in diabetic mice.

Methods

After diabetes induction with streptozotocin and high fat diet, both low density lipoprotein receptor (LDLR)−/− and apoE female mice were randomized to: AGE-LDL immunization with aluminum hydroxide (Alum) adjuvant; Alum alone; or PBS.

Results

AGE-LDL immunization: significantly reduced AS; induced specific plasma IgM and IgG antibodies; upregulated splenic Th2, Treg and IL-10 levels, without altering Th1 or Th17 cells; and increased serum high density lipoprotein(HDL) while numerically lowering HbA1c levels.

Conclusions

Subcutaneous immunization with AGE-LDL significantly inhibits atherosclerosis progression in hyperlipidemic diabetic mice possibly through activation of specific humoral and cell mediated immune responses and metabolic control improvement.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-014-0151-6) contains supplementary material, which is available to authorized users.

Natural IgM: beneficial autoantibodies for the control of inflammatory and autoimmune disease

Natural IgM are highly represented in the circulation at birth, and these often autoreactive antibodies have been postulated to have innate-like properties and play crucial roles in apoptotic cell clearance, tissue homeostasis, and immune modulation. This review summarizes the known properties of these IgM autoantibodies, and the evidence that these anti-apoptotic cell IgM natural antibodies can regulate inflammatory responses through ancient pathways of the innate immune system that first arose long before the initial emergence of the adaptive immune system. While the regulatory contributions of these natural IgM autoantibodies are certainly not an essential and fundamental component of host defenses, these provide an additional layer to further protect the host. More importantly, these IgM antibody responses are highly inducible and their up-regulation can be a powerful means for the host to survive in a setting of chronic inflammation. The observed beneficial clinical associations for cardiovascular disease and autoimmunity, as well as opportunities for potential therapeutic implications are discussed.

Bone marrow deficiency of MCPIP1 results in severe multi-organ inflammation but diminishes atherogenesis in hyperlipidemic mice

Objective

MCPIP1 is a newly identified protein that profoundly impacts immunity and inflammation. We aim to test if MCPIP1 deficiency in hematopoietic cells results in systemic inflammation and accelerates atherogenesis in mice.

Approach and Results

After lethally irradiated, LDLR^−/− mice were transplanted with bone marrow cells from either wild-type or MCPIP1^−/− mice. These chimeric mice were fed a western-type diet for 7 weeks. We found that bone marrow MCPIP1^−/− mice displayed a phenotype similar to that of whole body MCPIP1^−/− mice, with severe systemic and multi-organ inflammation. However, MCPIP1^−/− bone marrow recipients developed >10-fold less atherosclerotic lesions in the proximal aorta than WT bone marrow recipients, and essentially no lesions in en face aorta. The diminishment in atherosclerosis in bone marrow MCPIP1^−/− mice may be partially attributed to the slight decrease in their plasma lipids. Flow cytometric analysis of splenocytes showed that bone marrow MCPIP1^−/− mice contained reduced numbers of T cells and B cells, but increased numbers of regulatory T cells, Th17 cells, CD11b+/Gr1+ cells and CD11b+/Ly6C^low cells. This overall anti-atherogenic leukocyte profile may also contribute to the reduced atherogenesis. We also examined the cholesterol efflux capability of MCPIP1 deficient macrophages, and found that MCPIP1deficiency increased cholesterol efflux to apoAI and HDL, due to increased protein levels of ABCA1 and ABCG1.

Conclusions

Hematopoietic deficiency of MCPIP1 resulted in severe systemic and multi-organ inflammation but paradoxically diminished atherogenesis in mice. The reduced atheroegensis may be explained by the decreased plasma cholesterol levels, the anti-atherogenic leukocyte profile, as well as enhanced cholesterol efflux capability. This study suggests that, while atherosclerosis is a chronic inflammatory disease, the mechanisms underlying atherogenesis-associated inflammation in arterial wall versus the inflammation in solid organs may be substantially different.