Effects of Exclusive Breastfeeding Promotion Interventions on Child Outcomes: A Systematic Review and Meta-Analysis

INTRODUCTION

Interventions promoting exclusive breastfeeding (EBF) may benefit infant health outcomes, but evidence is inconsistent. The objective of this review was to assess the effect of interventions promoting EBF on health outcomes in infants and children under 7 years of age.

METHODS

A literature search was conducted using EMBASE, MEDLINE, CINAHL, Cochrane Central, Cochrane Database of Systematic Reviews, and WHO International Clinical Trials Registry Platform from inception to April 2022. Inclusion criteria were randomized or cluster-randomized controlled trials aiming to increase EBF that reported effects on offspring growth, morbidity, and/or mortality up to age 7 years. The primary outcome was infant/child growth. Secondary outcomes were infant morbidity and mortality and EBF rates. Data were pooled using a random-effects model.

RESULTS

Thirty-two studies (40 papers) were identified. No effect on infant/child growth was observed. EBF promotion interventions significantly improved EBF rates up to 6 months (n = 25; OR 3.15; 95% CI: 2.36, 4.19) and significantly reduced the odds of respiratory illness at 0-3 months by 59% (n = 2; OR 0.41; 95% CI: 0.20, 0.84) but not at later time-points. A borderline significant effect was observed for diarrhea (n = 12; OR 0.84; 95% CI: 0.70, 1.00). Effects on hospitalizations or mortality were not significant.

DISCUSSION/CONCLUSION

EBF promotion interventions improve EBF rates and might yield modest reductions in infant morbidity without affecting infant/child growth. Future studies should investigate the cost-effectiveness of these interventions and examine potential benefits on other health outcomes.

Diet-Nutrition Information Seeking, Source Trustworthiness, and Eating Behavior Changes: An International Web-Based Survey

To understand the extent to which different sources of diet and nutrition information are sought, trusted, and relied upon for making dietary changes, the present international web-based survey study gauged participants' (n = 3419) diet-nutrition information-seeking behaviors from 22 interpersonal and general sources with varying quality, trust levels in these sources, and reliance on each source for making dietary changes. Qualitative insights were also captured regarding trustworthiness formation. The results revealed a disconnect between source popularity and perceived trustworthiness. While nutrition-health websites, Google-Internet searches, and diet-health books were most commonly consulted, participants placed the highest level of trust in nutrition scientists, nutrition professionals, and scientific journals, suggesting that frequent information seeking from a subpar source may not be a reliable predictor of the level of trust assigned to it. Although the frequency of source-seeking behaviors and source trustworthiness both contributed to dietary changes, the latter appeared to have a more pronounced influence. When a source was less trusted, there was a reduced likelihood of relying on it for changing diet. Additionally, source seeking may not always translate into effective dietary change, as shown by the less strong correlation between the two. These associations significantly differed depending on the source.

Behavioral and Psychological Factors Affecting Weight Loss Success

PURPOSE OF REVIEW

There is a large variability between individuals in the weight loss response to any given diet treatment, which fuels interest into personalized or precision nutrition. Although most efforts are directed toward identifying biological or metabolic factors, several behavioral and psychological factors can also be responsible for some of this interindividual variability.

RECENT FINDINGS

There are many factors that can influence the response to dietary weight loss interventions, including factors related to eating behavior (emotional eating, disinhibition, restraint, perceived stress), behaviors and societal norms related to age and sex, psychological and personal factors (motivation, self-efficacy, locus of control, self-concept), and major life events. The success of a weight loss intervention can be influenced by many psychological and behavioral constructs and not merely by physiological factors such as biology and genetics. These factors are difficult to capture accurately and are often overlooked. Future weight loss studies should consider assessing such factors to better understand the underlying reasons for the large interindividual variability to weight loss therapy.

The impact of living through COVID-19 pandemic on mental health, food insecurity, loneliness and health behaviours in people with obesity

BACKGROUND

The COVID-19 pandemic has negatively impacted people living with obesity. The aim was to examine the continued impact of the COVID-19 pandemic on the mental health of people living with obesity and associations with food insecurity, loneliness and health-related behaviours.

METHODS

The study recruited 1187 UK adults living with obesity who completed an online survey, which examined mental health and associations with food insecurity, loneliness and health-related behaviours from July 2020 (end of the first lockdown in the United Kingdom) to the point they completed the survey in 2021. Regression analyses were used to examine relationships between outcome variables and demographic factors, and hierarchical linear regression models were used to assess levels of loneliness, depression and well-being.

RESULTS

Participants reported worse loneliness, depression, well-being and food insecurity compared to pre-COVID. However, participants reported attempting to lose weight, healthier food shopping, diet and increased physical activity. Quality and quantity of sleep deteriorated compared to prior to COVID-19.

CONCLUSIONS

Adults living with obesity in the United Kingdom report a continued negative impact of the COVID-19 pandemic upon their mental health together with increased loneliness and food insecurity. However, our findings suggest that UK adults living with obesity have increased their engagement in positive health behaviours and were attempting to lose weight.

Effective strategies in ending weight stigma in healthcare

Weight stigma impacts negatively healthcare quality and hinders public health goals. The aim of this review was to identify strategies for minimizing weight bias among healthcare professionals and explore future research directions. An electronic search was performed in PubMed, PsycINFO and Scopus (until June 2020). Studies on weight stigma reduction in healthcare students, trainees and professionals were assessed based on specific inclusion and exclusion criteria. A narrative synthesis was undertaken to analyze emerging themes. We identified five stigma reduction strategies in healthcare: (i) increased education, (ii) causal information and controllability, (iii) empathy evoking, (iv) weight-inclusive approach, and (v) mixed methodology. Weight stigma needs to be addressed early on and continuously throughout healthcare education and practice, by teaching the genetic and socioenvironmental determinants of weight, and explicitly discussing the sources, impact and implications of stigma. There is a need to move away from a solely weight-centric approach to healthcare to a health-focused weight-inclusive one. Assessing the effects of weight stigma in epidemiological research is equally important. The ethical argument and evidence base for the need to reduce weight stigma in healthcare and beyond is strong. Although evidence on long-term stigma reduction is emerging, precautionary action is needed.

Diet and Systemic Lupus Erythematosus (SLE): From Supplementation to Intervention

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease characterised by immune dysregulation affecting multiple organs. Current anti-inflammatory treatments used in SLE are associated with unwanted side-effects. Dietary supplementation has been suggested as a safe and effective addition to conventional treatment, but evidence of efficacy in SLE or preventing associated comorbidities is uncertain.

METHODS

We identified literature on clinical trials focused on nutritional interventions in SLE aiming to improve inflammation and comorbidities. A systematic-type search on Embase, Medline, and the Cochrane Library, was conducted to identify nutritional interventions among SLE patients in the past 15 years that met our inclusion criteria.

RESULTS

We identified 2754 articles, of which 14 were eligible for inclusion based on our set criteria and were subsequently quality assessed. Vitamin D or E supplementation was associated with respective improvement of inflammatory markers or antibody production, but not disease activity scores in most studies. Despite their expected synergistic actions, the addition of curcumin on vitamin D supplementation had no additional effects on disease activity or inflammatory markers. Trials of omega-3 fatty acid supplementation presented significant reductions in ESR, CRP, disease activity, inflammatory markers, and oxidative stress, and improved lipid levels and endothelial function, while a low glycaemic index (GI) diet showed evidence of reduced weight and improved fatigue in patients.

CONCLUSIONS

Different dietary guidelines can therefore be implicated to target specific SLE symptoms or therapeutic side-effects. This systematic review highlights the scarcity of larger and longer in duration trials with homogenous methodologies and verifiable outcomes to assess disease progression.

Cannabinoid interventions for improving cachexia outcomes in cancer: a systematic review and meta-analysis

Cancer-associated cachexia (CAC) is a wasting syndrome characterized by involuntary weight loss and anorexia. Clear definition and diagnostic criteria for CAC are lacking, which makes it difficult to estimate its prevalence, to interpret research and to compare studies. There is no standard treatment to manage CAC, but previous studies support the use of cannabinoids for cachexia in other chronic diseases including HIV and multiple sclerosis. However, only a few randomized controlled trials (RCTs) and one meta-analysis of this intervention in cancer populations are available. Non-randomized studies of interventions (NRSIs) are often excluded from reviews due to variable methodology and potential for biases. This review aimed to consider NRSIs alongside RCTs to provide a complete summary of the available evidence that clinical decision makers could use in future investigations. Literature searches were conducted using three databases for relevant RCTs or NRSIs according to Cochrane methodology. Abstract and full texts of retrieved manuscripts were selected and retrieved by two investigators based on the PRISMA-A guidelines, and risk of bias and quality of evidence assessments were performed. Outcome data on weight, appetite, quality of life, performance status, adverse effects, and mortality were combined by narrative synthesis and meta-analysis where possible. Ten studies were included, four of which were RCTs and six NRSIs matching the eligibility criteria. Very low-quality evidence from meta-analysis suggested no significant benefits of cannabinoids for appetite compared with control (standardized mean difference: -0.02; 95% confidence interval: -0.51, 0.46; P = 0.93). Patient-reported observations from NRSIs suggested improvements in appetite. Another meta-analysis of moderate quality evidence showed that cannabinoids were significantly less efficient than active or inactive control on quality of life (standardized mean difference: -0.25; 95% confidence interval: -0.43, -0.07; P = 0.007). The effectiveness of cannabinoids alone to improve outcomes of CAC remains unclear. Low-quality evidence from both RCTs and NRSIs shows no significant benefits of cannabinoids for weight gain, appetite stimulation, and better quality of life, three important outcomes of cachexia. Higher quality research integrating cannabinoids into multi-modal therapies may offer better opportunities for developing CAC-specific treatments. This review also highlights that findings from non-randomized studies of interventions (NRSIs) can provide evidence of the effects of an intervention and advocate for the feasibility of larger RCTs.

Plant-based dietary changes may improve symptoms in patients with systemic lupus erythematosus

INTRODUCTION

Previous studies have reported that patients affected by systemic lupus erythematosus (SLE) are interested in using diet to treat fatigue, cardiovascular disease and other symptoms. However, to date, there is insufficient information regarding the ways for patients to modify their diet to improve SLE symptoms. We investigated the relationship between the eating patterns of SLE patients and their self-reported disease symptoms and general aspects of health.

METHODS

A UK-based, online survey was developed, in which patients with SLE were asked about their attitudes and experiences regarding their SLE symptoms and diet.

RESULTS

The majority (>80%) of respondents that undertook new eating patterns with increased vegetable intake and/or decreased intake of processed food, sugar, gluten, dairy and carbohydrates reported benefiting from their dietary change. Symptom severity ratings after these dietary changes were significantly lower than before (21.3% decrease, p<0.0001). The greatest decreases in symptom severity were provided by low/no dairy (27.1% decrease), low/no processed foods (26.6% decrease) and vegan (26% decrease) eating patterns (p<0.0001). Weight loss, fatigue, joint/muscle pain and mood were the most cited symptoms that improved with dietary change.

CONCLUSION

SLE patients who changed their eating patterns to incorporate more plant-based foods while limiting processed foods and animal products reported improvements in their disease symptoms. Thus, our findings show promises in using nutrition interventions for the management of SLE symptoms, setting the scene for future clinical trials in this area. Randomised studies are needed to further test whether certain dietary changes are effective for improving specific symptoms of SLE.

The Interplay between Housing Environmental Attributes and Design Exposures and Psychoneuroimmunology Profile-An Exploratory Review and Analysis Paper in the Cancer Survivors' Mental Health Morbidity Context

Adult cancer survivors have an increased prevalence of mental health comorbidities and other adverse late-effects interdependent with mental illness outcomes compared with the general population. Coronavirus Disease 2019 (COVID-19) heralds an era of renewed call for actions to identify sustainable modalities to facilitate the constructs of cancer survivorship care and health care delivery through physiological supportive domestic spaces. Building on the concept of therapeutic architecture, psychoneuroimmunology (PNI) indicators-with the central role in low-grade systemic inflammation-are associated with major psychiatric disorders and late effects of post-cancer treatment. Immune disturbances might mediate the effects of environmental determinants on behaviour and mental disorders. Whilst attention is paid to the non-objective measurements for examining the home environmental domains and mental health outcomes, little is gathered about the multidimensional effects on physiological responses. This exploratory review presents a first analysis of how addressing the PNI outcomes serves as a catalyst for therapeutic housing research. We argue the crucial component of housing in supporting the sustainable primary care and public health-based cancer survivorship care model, particularly in the psychopathology context. Ultimately, we illustrate a series of interventions aiming at how housing environmental attributes can trigger PNI profile changes and discuss the potential implications in the non-pharmacological treatment of cancer survivors and patients with mental morbidities.

Negative impact of the first COVID-19 lockdown upon health-related behaviours and psychological wellbeing in people living with severe and complex obesity in the UK

BACKGROUND

Coronavirus disease 2019 (COVID-19) has led to unprecedented changes in the way we live, particularly for people at higher risk of severe illness from COVID-19. People with pre-existing health conditions have been markedly impacted and, in some instances, left unsupported due to reduced provision of routine healthcare services. People living with obesity (PLWO) are identified as at higher risk of severe illness from COVID-19 infection. Currently, there is a paucity of evidence about the impact of the first COVID-19 lockdown on PLWO, including those accessing weight management and bariatric surgery services (WMS).

METHODS

543 adults (16-80 years) with obesity (BMI ≥ 30 kg/m²) were recruited between 14th May and 9th July 2020 through social media advertisements, professional and patient obesity organisations and WMS. Participants completed an online survey regarding the impact of the first COVID-19 lockdown upon, mental health, well-being, health-related behaviours, risk mitigating behaviours, access to WMS and weight stigma.

FINDINGS

During the first COVID-19 lockdown, the majority of PLWO reported deterioration of their mental health and health-related behaviours such as diet, physical activity (PA) and sleep. With 55% reporting an unhealthier diet, 61% reduced PA and 80% worsening of their sleep. Higher depression and lower wellbeing scores were found to associate with the greatest adverse impact upon health-related behaviours. PLWO who were attending WMS prior to the first lockdown reported a greater deterioration of their diet, with nearly 50% reporting worsening of their diet and PA worsening compared to PLWO who were not attending WMS. Most participants took two or more risk mitigating actions (73%). PLWO attending WMS reported reduced access (44%) with insufficient information (49%) from their clinical service providers. The majority of participants reported no change in perceived weight stigma.

INTERPRETATION

This study shows the detrimental impact of the first COVID-19 lockdown on PLWO in relation to health-related behaviours, mental health and access to WMS. Our findings show that PLWO with poor mental health and those attending WMS were most adversely impacted and highlights the need for greater mental health support and continued provision of support from WMS for PLWO during future lockdowns.

FUNDING

This research was funded through National Institute for Health Research University College London Hospitals Biomedical Research Centre funding.

EP35 What do patients with lupus know about cardiovascular risk: could dietary modification be a promising therapeutic?

Background

Cardiovascular disease is the leading cause of mortality for patients with lupus. Understanding increased cardiovascular risk (CVR) in autoimmune diseases could improve CVR management in patients. The objective of a patient-focused event was to explore patient opinions about CVR and potential treatment options. A secondary objective was to learn about lupus patient experiences with diet including their opinion on considering diet as a therapeutic.

Methods

We hosted a patient event promoted through social media, relevant charities, hospitals and research groups. 13 patients with lupus and/or Sjögren’s syndrome attended and were asked about CVR using a questionnaire and round table discussion with researchers, clinicians and dietitians. In addition, a 15-question diet-based online survey was made publicly available for 3 weeks promoted through the same methods as the patient event.

Results

Sixty percent of patients were aware of the increased CVR associated with autoimmune rheumatic disease and 60% stated that their doctor had spoken to them about CVR. 73% thought that it was important for them to be aware of this increased CVR. When asked about medication to reduce CVR; no patients wanted to take a statin (lipid-lowering drug), however, 70% of patients would take statins if advised by their doctor. Conversely, respondents were more positive about using diet or taking a dietary supplement to reduce CVR; 71% would change their diet and 57% would take a supplement either on their own accord or on advice from health professionals. Some patients had already made changes to their diet to reduce their CVR, including reducing fat and increasing fruit and vegetable consumption. All attendees were prepared to participate in a clinical study using diet modification strategies, having vascular scans to assess atherosclerosis and provide blood samples for CVR research in lupus. An online survey was used to further assess lupus patient opinion on modifying their diet depending on their CVR. 284 responses were received over 3 weeks. Patients reported there was a lack of clinical counselling regarding diet with only 24% of patients stating that their doctor had spoken to them about diet. Despite this, 100% of patients stated that they would change their diet if they knew it would help their symptoms and 83% would take part in a diet-based clinical trial, supporting the results from the face-to-face patient event. Text analysis of patient research suggestions identified an interest in using diet to manage fatigue and disease activity.

Conclusion

This multidisciplinary event and online survey successfully gathered patient information regarding CVR and diet. The opinions and comments provided evidence that patients support further research in cardiovascular studies, a demand for increased CVR and dietary clinical counselling and a preference to changing their diet, whilst avoiding medication, to reduce their CVR.

Disclosures

G.A. Robinson None. E. Chocano Navarro None. K. Waddington None. T. Mcdonnell None. C. Wincup None. L. Martin-Gutierrez None. A. Maggio None. E. McLoughlin None. L. Rosser None. M. Naja None. D.A. Isenberg None. A.Z. Kalea None. C. Ciurtin None. I. Pineda-Torra None. E.C. Jury None.

Diet and lupus: what do the patients think?

Objectives

Cardiovascular disease is the leading cause of mortality in patients with systemic lupus erythematosus. Therefore, using diet to control blood lipid levels and modify cardiovascular disease risk could be a promising therapeutic strategy to control disease symptoms. The primary objective of this study was to learn about systemic lupus erythematosus patient experiences with diet, including their opinion on considering diet as a therapeutic option. The secondary objective was to obtain this information in a cost- and time-effective manner.

Methods

A lay summary and a 15-question diet-based online survey were publicly available for 3 weeks. Social media was used to promote the survey through relevant charities, hospitals and research groups.

Results

A total of 300 responses were received, 284 from patients with systemic lupus erythematosus. Patients reported that there was a lack of clinical counselling regarding diet, with only 24% stating their doctor had spoken to them about diet. Despite this, 100% of patients stated they would change their diet if they knew it would help their symptoms and 83% would take part in a future diet-based clinical trial. Text analysis of patient research suggestions identified a particular interest in using diet to treat fatigue and manage disease flares.

Conclusions

This project successfully gathered patient information regarding diet and systemic lupus erythematosus over a short timeframe using an anonymous social media platform. The survey provided evidence that patients support further research and potential diet intervention studies investigating the effect of diet on the symptoms of systemic lupus erythematosus.

Apelinergic system in the kidney: implications for diabetic kidney disease

The bioactive peptides of the apelinergic system and its receptor APJ have been shown to play a protective role in experimental cardiovascular and diabetic kidney disease (DKD). Mechanisms of this renoprotective effect remain to be elucidated. In this study, we examined the localization of APJ within the normal kidney and its kidney expression in the db/db model of DKD. The effect of hyperglycemia and angiotensin II on APJ was examined in cultured podocytes. In the glomerulus, APJ colocalized with podocyte but not endothelial cell markers. In podocytes stimulated with Pyr1 Apelin-13, a change in the phosphorylation status of the signaling proteins, AKT, ERK, and p70S6K, was observed with an increase 15 min after stimulation. Apelin-13 decreased activity of Caspase-3 in podocytes after high glucose treatment reflecting an antiapoptotic effect of APJ stimulation. In podocytes, APJ mRNA was downregulated in high glucose, when compared to normal glucose conditions and exposure to angiotensin II led to a further significant decrease in APJ mRNA. APJ and preproapelin mRNA levels in kidneys from db/db mice were markedly decreased along with decreased tubular APJ protein by western blotting and immunostaining when compared to db/m controls. In conclusion, the apelinergic system is decreased in kidneys from db/db mice. Within the glomerulus, APJ is mainly localized in podocytes and in this cell type its activation by Apelin-13 abolishes the proapoptotic effect of high glucose, suggesting a potential therapeutic role of apelin and emerging agonists with extended half-life for therapy of DKD.

Nutriepigenetics and cardiovascular disease

PURPOSE OF REVIEW

We present a current perspective of epigenetic alterations that can lead to cardiovascular disease (CVD) and the potential of dietary factors to counteract their actions. In addition, we discuss the challenges and opportunities of dietary treatments as epigenetic modifiers for disease prevention and therapy.

RECENT FINDINGS

Recent epigenome-wide association studies along with candidate gene approaches and functional studies in cell culture and animal models have delineated mechanisms through which nutrients, food compounds and dietary patterns may affect the epigenome. Several risk factors for CVD, including adiposity, inflammation and oxidative stress, have been associated with changes in histone acetylation, lower global DNA methylation levels and shorter telomere length. A surplus of macronutrients such as in a high-fat diet or deficiencies of specific nutrients such as folate and other B-vitamins can affect the activity of DNA methyltransferases and histone-modifying enzymes, affecting foetal growth, glucose/lipid metabolism, oxidative stress, inflammation and atherosclerosis. Bioactive compounds such as polyphenols (resveratrol, curcumin) or epigallocatechin may activate deacetylases Sirtuins (SIRTs), histone deacetylases or acetyltransferases and in turn the response of inflammatory mediators. Adherence to cardioprotective dietary patterns, such as the Mediterranean diet (MedDiet), has been associated with altered methylation and expression of genes related to inflammation and immuno-competence.

SUMMARY

The mechanisms through which nutrients and dietary patterns may alter the cardiovascular epigenome remain elusive. The research challenge is to determine which of these nutriepigenetic effects are reversible, so that novel findings translate into effective dietary interventions to prevent CVD or its progression.

Identification of the Functional Variant(s) that Explain the Low-Density Lipoprotein Receptor (LDLR) GWAS SNP rs6511720 Association with Lower LDL-C and Risk of CHD

Background

The Low-Density Lipoprotein Receptor (LDLR) SNP rs6511720 (G>T), located in intron-1 of the gene, has been identified in genome-wide association studies (GWAS) as being associated with lower plasma levels of LDL-C and a lower risk of coronary heart disease (CHD). Whether or not rs6511720 is itself functional or a marker for a functional variant elsewhere in the gene is not known.

Methods

The association of LDLR SNP rs6511720 with incidence of CHD and levels of LDL-C was determined by reference to CARDIoGRAM, C4D and Global lipids genetics consortium (GLGC) data. SNP annotation databases were used to identify possible SNP function and prioritization. Luciferase reporter assays in the liver cell line Huh7 were used to measure the effect of variant genotype on gene expression. Electrophoretic Mobility Shift Assays (EMSAs) were used to identify the Transcription Factors (TFs) involved in gene expression regulation.

Results

The phenotype-genotype analysis showed that the rs6511720 minor allele is associated with lower level of LDL-C [beta = -0.2209, p = 3.85 x10^-262], and lower risk of CHD [log (OR) = 0.1155, p = 1.04 x10^-7]. Rs6511720 is in complete linkage. Rs6511720 is in complete linkage disequilibrium (LD) with three intron-1 SNPs (rs141787760, rs60173709, rs57217136). Luciferase reporter assays in Huh7 cells showed that the rare alleles of both rs6511720 and rs57217136 caused a significant increase in LDLR expression compared to the common alleles (+29% and +24%, respectively). Multiplex Competitor-EMSAs (MC-EMSA) identified that the transcription factor serum response element (SRE) binds to rs6511720, while retinoic acid receptor (RAR) and signal transducer and activator of transcription 1 (STAT1) bind to rs57217136.

Conclusion

Both LDLR rs6511720 and rs57217136 are functional variants. Both these minor alleles create enhancer-binding protein sites for TFs and may contribute to increased LDLR expression, which is consequently associated with reduced LDL-C levels and 12% lower CHD risk.

Guidelines for the functional annotation of microRNAs using the Gene Ontology

MicroRNA regulation of developmental and cellular processes is a relatively new field of study, and the available research data have not been organized to enable its inclusion in pathway and network analysis tools. The association of gene products with terms from the Gene Ontology is an effective method to analyze functional data, but until recently there has been no substantial effort dedicated to applying Gene Ontology terms to microRNAs. Consequently, when performing functional analysis of microRNA data sets, researchers have had to rely instead on the functional annotations associated with the genes encoding microRNA targets. In consultation with experts in the field of microRNA research, we have created comprehensive recommendations for the Gene Ontology curation of microRNAs. This curation manual will enable provision of a high-quality, reliable set of functional annotations for the advancement of microRNA research. Here we describe the key aspects of the work, including development of the Gene Ontology to represent this data, standards for describing the data, and guidelines to support curators making these annotations. The full microRNA curation guidelines are available on the GO Consortium wiki (http://wiki.geneontology.org/index.php/MicroRNA_GO_annotation_manual).

Upregulation of gingival tissue miR-200b in obese periodontitis subjects

Increased local immune and inflammatory responses in obese individuals with periodontitis may explain the aggressive clinical presentation and altered treatment response when compared to that of normal weight subjects. Our goal was to identify any differences in microRNA (miRNA) expression profiles of gingival tissue in periodontitis when obesity is present, which may suggest novel molecular pathways that this miRNA network may affect. Total RNA was extracted from gingival tissue biopsies collected from normal weight and obese individuals with periodontitis; miRNA expression profiling was performed with Affymetrix GeneChip miRNA 3.0 arrays; and results were validated with quantitative reverse transcription polymerase chain reaction (qRT-PCR). In silico identification of previously confirmed miRNA gene targets was conducted through miRTarBase and miRWalk databases, and pathway enrichment analysis identified enriched miRNA gene sets. Expression of selected genes in the same biopsy samples was tested with qRT-PCR. The gingival tissue miRNA profile of obese patients, compared to that of normal weight patients, showed 13 upregulated and 22 downregulated miRNAs, among which miR-200b was validated by qRT-PCR to be significantly increased in obesity. Functional analysis of 51 experimentally validated miR-200b gene targets identified enrichment of genes involved in cell motility, differentiation, DNA binding, response to stimulus, and vasculature development pathways not previously identified in the obesity-specific disease profile. Furthermore, the expression of the miR-200b gene targets ZEB1/2, GATA2, and KDR was confirmed by qRT-PCR as being lower in obese patients with periodontitis versus normal weight patients, suggesting a role of miR-200b in regulation of a set of gene targets and biological pathways relevant to wound healing and angiogenesis. Functional studies to explore the role of miR-200b in the above processes may offer new insights on putative therapeutic targets for this group of patients.

Attenuation of alpha-adrenergic-induced vasoconstriction by dietary wild blueberries (Vaccinium angustifolium) is mediated by the NO-cGMP pathway in spontaneously hypertensive rats (SHRs)

The role of wild blueberries (WB) on key signaling steps of nitric oxide (NO) and cyclooxygenase (COX) pathways was examined in spontaneously hypertensive rats (SHRs) after eight weeks on a control (C) or an 8% w/w WB diet. Aortic rings from SHRs were stimulated with phenylephrine (Phe) in the absence or presence of inhibitors of: soluble guanylyl cyclase (sGC), phosphodiesterase-5 (PDE(5)), prostaglandin I(2) (PGI(2)) synthase and thromboxane A(2) (TXA(2)) synthase. Additionally, enzymatic activities in these pathways were determined by the concentration of NO, cyclic guanosine monophosphate (cGMP), PGI(2) and TXA(2). In the WB-fed SHR, attenuation of Phe-induced vasoconstriction was mediated by an increased synthesis or preservation of cGMP. Despite an increased release of PGI(2) in the WB group, neither inhibition of PGI(2) or TXA(2) synthase resulted in a different response to Phe between the control and the WB rings. Hence, in the SHR, WB decrease Phe-mediated vasoconstriction under basal conditions by enhancing NO-cGMP signaling without a significant involvement of the COX pathway.

Functional analysis of two PLA2G2A variants associated with secretory phospholipase A2-IIA levels

BACKGROUND

Secretory phospholipase A2 group IIA (sPLA2-IIA) has been identified as a biomarker of atherosclerosis in observational and animal studies. The protein is encoded by the PLA2G2A gene and the aim of this study was to test the functionality of two PLA2G2A non-coding SNPs, rs11573156 C>G and rs3767221 T>G where the rare alleles have been previously associated with higher and lower sPLA2-IIA levels respectively.

METHODOLOGY/PRINCIPAL FINDINGS

Luciferase assays, electrophoretic mobility shift assays (EMSA), and RNA expression by RT-PCR were used to examine allelic differences. For rs3767221 the G allele showed ∼55% lower luciferase activity compared to the T allele (T = 62.1 (95% CI 59.1 to 65.1) G = 27.8 (95% CI 25.0 to 30.6), p = 1.22×10⁻³⁵, and stronger EMSA binding of a nuclear protein compared to the T-allele. For rs11573156 C >G there were no luciferase or EMSA allelic differences seen. In lymphocyte cell RNA, from individuals of known rs11573156 genotype, there was no allelic RNA expression difference for exons 5 and 6, but G allele carriers (n = 7) showed a trend to lower exon 1-2 expression compared to CC individuals. To take this further, in the ASAP study (n = 223), an rs11573156 proxy (r² = 0.91) showed ∼25% higher liver expression of PLA2G2A (1.67×10⁻¹⁷) associated with the G allele. However, considering exon specific expression, the association was greatly reduced for exon 2 (4.5×10⁻⁵) compared to exons 3-6 (10⁻¹⁰ to 10⁻²⁰), suggesting rs11573156 G allele-specific exon 2 skipping.

CONCLUSION

Both SNPs are functional and provide useful tools for Mendelian Randomisation to determine whether the relationship between sPLA2-IIA and coronary heart disease is causal.

Food consumption patterns in Mediterranean adolescents: are there differences between overweight and normal-weight adolescents?

OBJECTIVE

To quantify food consumption (based on food group classification) during several time periods in a sample of adolescents and to identify potential differences in food patterns between normal-weight and overweight participants.

DESIGN

Cross-sectional study. Participants were classified as normal weight and overweight/obese. Dietary intake was assessed by 3-day food records and analyzed at the food group level for 7 different time periods. To exploit the time dimension of the data and to further control for the influence of other covariates, the authors estimated a random effects regression model for panel data.

PARTICIPANTS

One hundred twenty students.

SETTING

Two high schools.

RESULTS

In multivariate analysis, no statistically significant differences were found between normal-weight and overweight adolescents with regard to their consumption patterns throughout the day. However, compared to females, male participants had higher intake of all food groups with the exception of fruit, and adolescents engaging in vigorous exercise tended to consume more servings from all food groups during any given time period.

CONCLUSIONS AND IMPLICATIONS

No preferential use of some food or food groups in specific day periods was found among overweight compared to normal-weight high school students.

The temporal effect of a wild blueberry (Vaccinium angustifolium)-enriched diet on vasomotor tone in the Sprague-Dawley rat

BACKGROUND AND AIMS

We have previously reported that wild blueberry (Vaccinium angustifolium)-enriched diets (WB) attenuate aortic adrenergic response through endothelial-mediated pathways. The duration of dietary intervention necessary to induce the positive changes on vasomotor tone has not been studied to date. Thus, our objective was to investigate the temporal effect of WB consumption on vascular function and reactivity in Sprague-Dawley (SD) rat aorta after 4 and 7 weeks of dietary treatment.

METHODS AND RESULTS

Forty male SD rats were randomly assigned to a control (AIN-93) (C) or a WB diet for 4 or 7 weeks. Vascular ring studies were conducted in 3-mm isolated rat aortic rings to investigate vasoconstriction induced by six doses of the α(1)-adrenergic agonist, L-phenylephrine (Phe, 10(-8)-3×10(-6) M) alone or in the presence of the NOS inhibitor, L-N(G)-monomethyl-arginine (L-NMMA, 10(-4)M). The maximum force of contraction (F(max)) and vessel sensitivity (pD(2)) were determined. Analysis of variance revealed no significant differences on F(max) after 4 weeks of the WB diet but only a significant increase in pD(2) in the absence of L-NMMA. Seven week WB consumption significantly attenuated contraction in response to L-Phe and resulted in lower pD(2). Inhibition of NOS induced a significant increase in the constrictor response in both diet groups at both time periods, with the WB group fed for 7 weeks having the greater response.

CONCLUSION

Thus wild blueberries incorporated into the diet at 8% w/w positively affect vascular smooth muscle contractility and sensitivity but these effects are evident only after 7 weeks of WB consumption.

Association of serum soluble receptor for advanced glycation end-products with subclinical cerebrovascular disease: the Northern Manhattan Study (NOMAS)

OBJECTIVE

Serum levels of the soluble receptor for advanced glycation end-products (sRAGE) have been associated with risk of cardiovascular disease. We hypothesized that sRAGE levels are associated with subclinical cerebrovascular disease in an ethnically diverse population.

METHODS

Clinically stroke-free participants in the multi-ethnic Northern Manhattan Study (NOMAS) underwent brain MRI to quantify subclinical brain infarcts (SBI) and white matter hyperintensity volume (WMHV) (n = 1102). Serum levels of sRAGE were measured by ELISA. Logistic and multiple linear regression were employed to estimate associations of sRAGE with SBI and WMHV, after adjusting for demographics and vascular risk factors.

RESULTS

Median sRAGE levels were significantly lower in Hispanics (891.9 pg/ml; n = 708) and non-Hispanic blacks (757.4 pg/ml; n = 197) than in non-Hispanic whites (1120.5 pg/ml; n = 170), and these differences remained after adjusting for other risk factors. Interactions were observed by race-ethnicity between sRAGE levels and MRI measurements, including for SBI in Hispanics (p = 0.04) and WMHV among blacks (p = 0.03). In Hispanics, increasing sRAGE levels were associated with a lower odds of SBI, with those in the upper sRAGE quartile displaying a 50% lower odds of SBI after adjusting for sociodemographic and vascular risk factors (p = 0.05). Among blacks, those in the upper quartile of sRAGE had a similarly reduced increased risk of SBI (p = 0.06) and greater WMHV (p = 0.04).

CONCLUSION

Compared to whites, Hispanics and blacks have significantly lower sRAGE levels, and these levels were associated with more subclinical brain disease. Taken together, these findings suggest sRAGE levels may be significantly influence by ethnicity. Further studies of sRAGE and stroke risk, particularly in minorities, are warranted.

A wild blueberry-enriched diet (Vaccinium angustifolium) improves vascular tone in the adult spontaneously hypertensive rat

The effect of a wild blueberry-enriched diet on vasoconstriction and vasorelaxation was examined in the adult, 20-week-old spontaneously hypertensive rat (SHR) after 8 weeks of a control (C) or an 8% wild blueberry (WB) diet. Nitric oxide (NO)- and cyclooxygenase (COX)-mediated aortic responses were examined ex vivo with the agonists L-phenylephrine (Phe) and acetylcholine (Ach), in the absence or presence of the NO synthase (NOS) inhibitor L-NG-monomethyl arginine (L-NMMA) or the COX inhibitor mefenamic acid (MFA). The vasoconstriction elicited by Phe was reduced in the WB group, attributed to the NO pathway, favoring a lower vascular tone under basal conditions. Acetylcholine-induced vasorelaxation in the WB group was possibly mediated through the COX, but not the NO pathway. These findings document the potential of wild blueberries to modify major pathways of vasomotor control and improve the vascular tone in the adult SHR with endothelial dysfunction.

Alternatively spliced RAGEv1 inhibits tumorigenesis through suppression of JNK signaling

Receptor for advanced glycation end products (RAGE) and its ligands are overexpressed in multiple cancers. RAGE has been implicated in tumorigenesis and metastasis, but little is known of the mechanisms involved. In this study, we define a specific functional role for an alternate splice variant termed RAGE splice variant 1 (RAGEv1), which encodes a soluble endogenous form of the receptor that inhibits tumorigenesis. RAGEv1 was downregulated in lung, prostate, and brain tumors relative to control matched tissues. Overexpressing RAGEv1 in tumor cells altered RAGE ligand stimulation of several novel classes of genes that are critical in tumorigenesis and metastasis. Additionally, RAGEv1 inhibited tumor formation, cell invasion, and angiogenesis induced by RAGE ligand signaling. Analysis of signal transduction pathways underlying these effects revealed marked suppression of c-jun-NH(2)-kinase (JNK) pathway signaling, and JNK inhibition suppressed signaling through the RAGE pathway. Tumors expressing RAGEv1 were significantly smaller than wild-type tumors and displayed prominently reduced activation of JNK. Our results identify RAGEv1 as a novel suppressor, the study of which may offer new cancer therapeutic directions.

Apelin and ACE2 in cardiovascular disease

Apelin is a peptide that has been identified as the endogenous ligand for the receptor APJ. The apelin/APJ system may be an important factor in the regulation of vascular tone and cardiovascular function. Studies on cultured cells and small animal models have revealed that apelin and APJ are localized in cardiomyocytes and vascular cells. The infusion of apelin affects vascular tone and blood pressure, with both central and peripheral actions. In clinical conditions such as heart failure and atherosclerosis, the gene expression of APJ and apelin, as well as the levels of circulating apelin, may be altered. The only known active homolog of ACE, ACE2, hydrolyzes apelin with similar potency to angiotensin II and, therefore, is responsible for the degradation of both peptides. Emerging data on a potential interaction between the two pathways suggest that the function of apelin/APJ in the vasculature may be relevant to cardiovascular disease, and identifying how this system is regulated could be useful clinically.

Inflammatory stress in primary venous and aortic endothelial cells of type 1 diabetic mice

OBJECTIVE

The progression of diabetes is associated with profound endothelial dysfunction. We tested the hypothesis that cellular stress would be detectable in ECs retrieved from arterial and venous vessels of diabetic mice.

METHOD

We describe a method for direct isolation of well-characterised aortic and venous ECs from mice in which cells are not subjected to propagation in culture.

RESULTS

Gene expression profiling, confirmed by real-time PCR, revealed a progressive increase in markers of injury within two main gene families, EC activation and EC apoptosis, in aortic and venous ECs recovered from diabetic versus non-diabetic mice. In short-term diabetes, Il1b mRNA transcripts were higher in aortic and venous ECs of diabetic mice versus controls. In long-term diabetes, casp-1 mRNA transcripts were higher in aortic and venous ECs of diabetic mice versus controls.

CONCLUSION

These data suggest that diabetes imparts diffuse endothelial perturbation in the arterial and venous endothelium.

Vascular reactivity is affected by dietary consumption of wild blueberries in the Sprague-Dawley rat

We have previously reported that consumption of blueberry-enriched (BB) diets attenuates the arterial contractile response to alpha(1)-adrenergic stimuli and affects vasomotor tone via endothelium-related pathways. The present study was designed to evaluate vascular function and responsiveness in aortas of weanling male Sprague-Dawley rats fed a control (C) or a BB diet for 7 weeks. Vascular ring studies were conducted in 3-mm isolated rat aortic ring preparations to investigate vasoconstriction induced by L-phenylephrine (Phe) (10(-8)-3 x 10(-6) M) and vasorelaxation induced by acetylcholine (ACh) (10(-8)-3 x 10(-6) M). Agonists were used alone and in the presence of nitric oxide (NO) synthase and cyclooxygenase (COX) inhibitors. We observed a significantly diminished vasoconstrictor response to Phe in aortic rings from rats fed the BB diet. Inhibition of NO synthase but not COX caused a significant increase in the constrictor response in both dietary groups, with the BB group having the greater response. Similarly, the participation of the NO pathway in endothelium-dependent vasorelaxation induced by ACh was greater in the rats fed a BB diet, while COX inhibition showed no effect on maximum ACh-induced vasorelaxation in any diet group. The vessel sensitivity of BB aortic rings to the vasoconstrictor and vasodilator was significantly reduced when compared to controls. We have concluded that diets enriched with blueberries, fed for 7 weeks in Sprague-Dawley rats, seem to affect NO metabolic pathways in the aorta at basal and stimulated levels.

Alternative splicing of the murine receptor for advanced glycation end-products (RAGE) gene

The alternative splicing of pre-mRNAs is a critical mechanism in genomic complexity, disease, and development. Studies of the receptor for advanced glycation end-products (RAGE) indicate that this gene undergoes a variety of splice events in humans. However, no studies have extensively analyzed the tissue distribution in other species or compared evolutionary differences of RAGE isoforms. Because the majority of studies probing RAGE function have been performed in murine models, we therefore performed studies to identify and characterize the splice variants of the murine RAGE gene, and we compared these to human isoforms. Here, using mouse tissues, we identified numerous splice variants including changes in the extracellular domain or the removal of the transmembrane and cytoplasmic domains, which produce soluble splice isoforms. Comparison of splice variants between humans and mice revealed homologous regions in the RAGE gene that undergo splicing as well as key species-specific mechanisms of splicing. Further analysis of tissue splice variant distribution in mice revealed major differences between lung, kidney, heart, and brain. To probe the potential impact of disease-like pathological states, we studied diabetic mice and report that RAGE splice variation changed dramatically, resulting in an increase in production of soluble RAGE (sRAGE) splice variants, which were not associated with detectable levels of sRAGE in murine plasma. In conclusion, we have determined that the murine RAGE gene undergoes extensive splicing with distinct splice isoforms being uniquely distributed in different tissues. These differences in RAGE splicing in both physiological and pathogenic states further expand our understanding of the biological repertoire of this receptor in health and disease.

Interaction of the RAGE cytoplasmic domain with diaphanous-1 is required for ligand-stimulated cellular migration through activation of Rac1 and Cdc42

Cellular migration is a fundamental process linked to diverse pathological states such as diabetes and its complications, atherosclerosis, inflammation, and cancer. The receptor for advanced glycation end products (RAGE) is a multiligand cell surface macromolecule which binds distinct ligands that accumulate in these settings. RAGE-ligand interaction evokes central changes in key biological properties of cells, including proliferation, generation of inflammatory mediators, and migration. Although RAGE-dependent signal transduction is critically dependent on its short cytoplasmic domain, to date the proximate mechanism by which this RAGE domain engages and stimulates cytoplasmic signaling pathways has yet to be identified. Here we show that the RAGE cytoplasmic domain interacts with Diaphanous-1 (Dia-1) both in vitro and in vivo. We employed the human RAGE cytoplasmic domain as "bait" in the yeast two-hybrid assay and identified the formin homology (FH1) domain of Dia-1 as a potential binding partner of this RAGE domain. Immunoprecipitation studies revealed that the RAGE cytoplasmic domain interacts with the FH1 domain of Dia-1. Down-regulation of Dia-1 expression by RNA interference blocks RAGE-mediated activation of Rac-1 and Cdc42 and, in parallel, RAGE ligand-stimulated cellular migration. Taken together, these findings indicate that the interaction of the RAGE cytoplasmic domain with Dia-1 is required to transduce extracellular environmental cues evoked by binding of RAGE ligands to their cell surface receptor, a chief consequence of which is Rac-1 and Cdc42 activation and cellular migration. Because RAGE and Dia-1 are implicated in the regulation of inflammatory, vascular, and transformed cell migration, these findings highlight this interaction as a novel target for therapeutic intervention in inflammation, atherosclerosis, diabetes, and cancer.

Vascular and inflammatory stresses mediate atherosclerosis via RAGE and its ligands in apoE-/- mice

Endothelial dysfunction is a key triggering event in atherosclerosis. Following the entry of lipoproteins into the vessel wall, their rapid modification results in the generation of advanced glycation endproduct epitopes and subsequent infiltration of inflammatory cells. These inflammatory cells release receptor for advanced glycation endproduct (RAGE) ligands, specifically S100/calgranulins and high-mobility group box 1, which sustain vascular injury. Here, we demonstrate critical roles for RAGE and its ligands in vascular inflammation, endothelial dysfunction, and atherosclerotic plaque development in a mouse model of atherosclerosis, apoE-/- mice. Experiments in primary aortic endothelial cells isolated from mice and in cultured human aortic endothelial cells revealed the central role of JNK signaling in transducing the impact of RAGE ligands on inflammation. These data highlight unifying mechanisms whereby endothelial RAGE and its ligands mediate vascular and inflammatory stresses that culminate in atherosclerosis in the vulnerable vessel wall.

Identification, classification, and expression of RAGE gene splice variants

The receptor for advanced glycation end-products (RAGE) is a single-transmembrane, multiligand receptor of the immunoglobulin superfamily. RAGE up-regulation is implicated in numerous pathological states including vascular disease, diabetes, cancer, and neurodegeneration. The understanding of the regulation of RAGE is important in both disease pathogenesis and normal homeostasis. Here, we demonstrate the characterization and identification of human RAGE splice variants by analysis of RAGE cDNA from tissue and cells. We identified a vast range of splice forms that lead to changes in the protein coding region of RAGE, which we have classified according to the Human Gene Nomenclature Committee (HGNC). These resulted in protein changes in the ligand-binding domain of RAGE or the removal of the transmembrane domain and cytosolic tail. Analysis of splice variants for premature termination codons reveals approximately 50% of identified variants are targeted to the nonsense-mediated mRNA decay pathway. Expression analysis revealed the RAGE_v1 variant to be the primary secreted soluble isoform of RAGE. Taken together, identification of functional splice variants of RAGE underscores the biological diversity of the RAGE gene and will aid in the understanding of the gene in the normal and pathological state.

Dietary manganese affects the concentration, composition and sulfation pattern of heparan sulfate glycosaminoglycans in Sprague-Dawley rat aorta

We examined the effect of dietary Mn on the composition and structure of heparan sulfate (HS) glycosaminoglycans (GAGs) of rat aorta. Animals were randomly assigned to either a Mn deficient (MnD), adequate (MnA) or supplemented (MnS) diet (Mn<1, 10-15 and 45-50 ppm, respectively). After 15 weeks, aortic tissue GAGs were isolated with papain digestion, alkaline borohydride treatment and anion-exchange chromatography. Cellulose acetate electrophoresis and treatment of the fractions with specific lyases revealed the presence of three GAG populations, i.e. hyaluronan (HA), heparan sulfate (HS) and galactosaminoglycans (GalAGs). Disaccharide composition of the HS fractions was determined by HPCE following treatment with heparin lyases I, II and III. In MnS aortas we observed increased concentration of total GalAGs and decreased concentration of HS and HA, when compared to MnA aortas. Aortas from MnD and MnA rats appeared to have similar distribution of individual GAGs. Heparan sulfate chains of MnS aortas contained higher (41%) concentration of non-sulfated units compared to MnA ones. Variable amounts of trisulfated and disulfated units were found only in MnD and MnA groups but not in MnS. Our results demonstrate that HS biosynthesis in the rat aorta undergoes marked structural modifications that depend upon dietary Mn intake. The reduced expression and undersulfation of HSPGs with Mn supplementation might indicate a reduced ability of vascular cells to interact with biologically active molecules such as growth factors. Alterations in cell-membrane binding ability to a variety of extracellular ligands might affect signal-transduction pathways and arterial functional properties.

Cyclo-oxygenase inhibition restores the attenuated vasodilation in manganese-deficient rat aorta

Previously we showed that manganese (Mn) deficiency enhances the arterial contractile response to alpha(1) adrenergic stimuli and affects vasomotor tone. The aim of this study was to test the hypothesis that dietary Mn deficiency inhibits the vasodilation pathways of rat aorta. Vascular ring studies were conducted in aortic rings from weanling male Sprague-Dawley rats that were fed either a Mn deficient (MnD) or a Mn adequate/control diet (MnA) (<1 and 12 mg/kg Mn, respectively) for a 14-wk period. We investigated endothelium-dependent vasodilation induced by acetylcholine (Ach; 10(-8) to 3 x 10(-6) mol/L) in isolated 3-mm aortic rings precontracted with l-phenylephrine (l-Phe; 10(-6) mol/L). Seven concentrations of Ach were used in the presence or absence of inhibitors of nitric oxide synthase and cyclo-oxygenase. After a second precontraction, 8 doses of sodium nitroprusside (SNP; 10(-8) to 10(-5) mol/L) were added to assess endothelium-independent vasodilation. We observed a decrease in Ach-induced and SNP-induced vasodilation in MnD rat aortas when compared with MnA rat aortas (P </= 0.05). Vessel sensitivity of MnD and MnA aortas to Ach was similar. The addition of l-arginine had no effect on nitric oxide-mediated vasodilation in either group. Nitric oxide synthase-inhibition blunted endothelium-dependent vasodilation to the same degree for both diet groups. Cyclo-oxygenase inhibition enhanced both Ach-induced and SNP-induced vasodilation of MnD rings compared with MnA aortic rings (P </= 0.05). Manganese inhibits the synthesis or activity of a prostanoid-derived vasoconstrictor, which seems to be present at basal and at stimulated levels. This effect is independent of membrane-related events. Our results provide further information on the critical role of Mn on vasomotor tone.

Wild blueberry-rich diets affect the contractile machinery of the vascular smooth muscle in the Sprague-Dawley rat

Weanling male Sprague-Dawley rats were randomly fed a control diet (AIN-93) (C) or a blueberry diet (B) for 13 weeks, or a reverse diet (R) (C diet for 13 weeks, switched to the B diet for 8 weeks). Aortas were excised, and two intact and two endothelium-denuded rings were immersed in tissue baths containing physiological salt solution at 37 degrees C and aerated with 95% O(2) and 5% CO(2) (pH 7.4). Following equilibration and preconditioning under 1.5-g preload, cumulative dose-response curves were generated with six doses of the alpha1-adrenergic receptor-selective agonist L-phenylephrine (L-Phe, 10(8)-3 x 10(-6) M) and relaxed with one dose of acetylcholine (3 x 10(-6) M) to assess intact endothelium. The maximum force of contraction (Fmax) and vessel sensitivity (pD(2)) were determined in intact and endothelium-denuded rings. A two-way analysis of variance test revealed that blueberry-fed animals (B and R diets) developed a significantly lower F (max) (0.873 +/- 0.0463 and 0.9266 +/- 0.0463 g, respectively) when contracted with L-Phe, compared with the animals on the C diet (1.109 +/- 0.0463 g) (P < .05). The pD(2) of the intact rings was not significantly different among diet groups. Additionally, diet did not significantly affect the mean F (max) or pD(2) of endothelium-denuded rings. Our results indicate for the first time that wild blueberries incorporated into the diet affect the vascular smooth muscle contractile machinery by suppressing the alpha1-adrenergic receptor agonist-mediated contraction while having no effect on membrane sensitivity of the endothelial or vascular smooth muscle cell layer. Furthermore, their mechanism of action seems to be accomplished through an endothelium-dependent pathway.

Wild blueberry (Vaccinium angustifolium) consumption affects the composition and structure of glycosaminoglycans in Sprague-Dawley rat aorta

It has been documented that increased intake of polyphenols may provide protection against coronary heart disease and stroke. Blueberries (Vaccinium angustifolium) are one of the richest sources of antioxidants among fruits and vegetables. Phenolic compounds from berry extracts inhibit human low density lipoprotein and liposome oxidation. Glycosaminoglycans (GAGs) and proteoglycans (PGs) are structural components of aortas with great structural diversity. Their interaction with compounds such as enzymes, cytokines, growth factors, proteins and lipoproteins and their subsequent role in degenerative diseases has been documented. We investigated the effects of a diet rich in blueberries on the content and structure of GAGs. Sprague-Dawley rats were fed either a control (C) or a blueberry (B) diet for 13 weeks. Aortic tissue GAGs were isolated with papain digestion, alkaline borohydride treatment and anion-exchange chromatography. Cellulose acetate electrophoresis and treatment of the fractions with specific lyases revealed the presence of three GAG populations, i.e. hyaluronan (HA), heparan sulfate (HS) and galactosaminoglycans (GalAGs). Disaccharide composition was determined by high-performance capillary electrophoresis following enzymatic degradation. A 13% higher amount of total GAGs in aortas of B-fed rats was attributed to a higher content of GalAGs (67%). Determination of the sulfated disaccharides showed an overall lower concentration of oversulfated disaccharides in both HS and GalAG populations in the aortas of the B group. Our results demonstrate for the first time that a diet rich in blueberries results in structural alterations in rat aortic tissue GAGs. These changes may affect cellular signal transduction pathways and could have major consequences for the biological function of GAG molecules within the vascular environment.

Dietary manganese suppresses α1 adrenergic receptor-mediated vascular contraction

We examined the effect of dietary manganese (Mn) on the vascular contractile machinery in rat thoracic aortas. Weanling male Sprague-Dawley rats were fed either an Mn-deficient (MnD), Mn-adequate (MnA) or Mn-supplemented (MnS) diet (<1, 10-15 and 45-50 ppm Mn, respectively). After 15 weeks on the diets the rats were sacrificed and 3-mm aortic rings were contracted in six cumulative doses of the alpha(1) adrenergic receptor agonist L-phenylephrine (l-Phe, 10(-8) to 3 x 10(-6) M) under 1.5-g preload and relaxed with one dose of acetylcholine (3 x 10(-6) M) to assess intact endothelium. The maximal force (F(max)) of contraction and relaxation, as well as the vessel sensitivity (pD(2)) were determined. Manganese deficiency, assessed by hepatic Mn content, significantly lowered the rate of animal growth. A two-way analysis of variance revealed that MnS animals developed lower F(max) when contracted with L-Phe compared with the MnD and MnA animals (P</=.001). Thus, dietary Mn at levels of 45-50 ppm affects the contractile machinery by reducing maximal vessel contraction to an alpha(1) adrenergic agonist. The observed pD(2) was significantly greater in the MnD group compared with the MnA and MnS animals (P</=.001). Thus, restriction of dietary Mn affects vascular sensitivity to the alpha(1) adrenergic receptor. Our results demonstrate for the first time that dietary Mn influences the receptor signaling pathways and contractile machinery of vascular smooth muscle cells in response to an alpha(1) adrenergic receptor.