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Dai J.,Indiana University | Dai J.,Indiana Center for Vascular Biology and Medicine | Dai J.,Emory Program in Cardiovascular Outcomes Research and Epidemiology | Dai J.,Emory University | And 11 more authors.
American Journal of Clinical Nutrition

Background: α-Linolenic acid (ALA) is associated with a low risk of cardiovascular disease; however, the underlying mechanism is not completely known. Objective: The objective was to examine whether habitual dietary ALA intake is associated with plasma concentrations of inflammatory biomarkers after control for shared genetic and common environmental factors. Design: We cross-sectionally studied 353 middle-aged male twins. Habitual diet was assessed with the Willett food-frequency questionnaire. Fasting plasma concentrations of interleukin-6 (IL-6) and its soluble receptor (sIL-6R), high-sensitivity C-reactive protein (hsCRP), and tumor necrosis factor-α (TNF-α) were measured. Linear mixed-effect regression analysis was used to partition the overall association into within- and between-pair associations. Results: A 1-g increment in habitual dietary ALA intake was associated with 11.0% lower concentrations of sIL-6R (P = 0.004) but not of IL-6 (P = 0.31), TNF-α (P = 0.16), or hsCRP (P = 0.36) after adjustment for energy intake, nutritional factors, known cardiovascular disease risk factors, and medications. After further control for shared genetic and common environmental factors by comparison of brothers within a twin pair, a twin with a 1-g higher ALA intake was likely to have 10.9% (95% CI: 3.7%, 17.6%; P = 0.004) lower sIL-6R concentrations than his co-twin with a low intake, whereas ALA intake was not significantly associated with plasma concentrations of IL-6, TNF-α, or hsCRP. These results were validated by using 1000 bootstrap samples. Conclusions: Habitual dietary ALA intake is inversely associated with plasma sIL-6R concentrations independent of shared genetic and common environmental influences. Lowering sIL-6R may be a mechanism underlying the cardioprotective properties of habitual dietary ALA. This study was registered at clinicaltrials.gov as NCT00017836. © 2010 American Society for Nutrition. Source

Dai J.,Indiana University Bloomington | Dai J.,Indiana Center for Vascular Biology and Medicine | Dai J.,Indiana University | Lampert R.,Yale University | And 4 more authors.
Circulation: Cardiovascular Quality and Outcomes

Background-Reduced heart rate variability (HRV), a measure of cardiac autonomic dysfunction, is a risk factor for coronary artery disease. Diet can influence HRV, but this association may be confounded by genetic and environmental factors. Methods and Results-We administered the Willett Food Frequency Questionnaire to 276 middle-aged male twins. We derived a score measuring the extent to which an individual's diet conformed to the Mediterranean diet following a published algorithm. The higher the score, the greater the similarity to the Mediterranean diet. All twins underwent 24-hour ambulatory ECG recording. Time and frequency domain measures of HRV were calculated. Mixed-effects regression was used to partition the association into between- and within-twin pair differences. After adjusting for energy intake, other nutritional factors, shared genes, and common environment, a 1-unit higher score was significantly associated with 3.9% to 13% higher time and frequency domain HRV parameters. Further controlling for known cardiovascular risk factors and use of fish oil supplements and medications did not substantially change the estimates. Conclusions-The Mediterranean dietary pattern is associated with higher HRV. © 2010 American Heart Association, Inc. Source

Merfeld-Clauss S.,Indiana Center for Vascular Biology and Medicine | Merfeld-Clauss S.,Center for Regenerative Medicine | Lupov I.P.,Indiana Center for Vascular Biology and Medicine | Lupov I.P.,Center for Regenerative Medicine | And 11 more authors.
Circulation Research

Rationale: Adipose stromal cells (ASC) are therapeutically potent progenitor cells that possess properties of pericytes. In vivo, ASC in combination with endothelial cells (EC) establish functional multilayer vessels, in which ASC form the outer vessel layer and differentiate into mural cells. Objective: To identify factors responsible for ASC differentiation toward the smooth muscle cell phenotype via interaction with EC. Methods and Results: An in vitro model of EC cocultivation with ASC was used, in which EC organized into vascular cords, accompanied by ASC migration toward EC and upregulation of α-smooth muscle actin, SM22α, and calponin expression. Conditioned media from EC-ASC, but not from EC cultures, induced smooth muscle cell protein expression in ASC monocultures. EC-ASC cocultivation induced marked accumulation of activin A but not transforming growth factor-β1 in conditioned media. This was attributed to induction of activin A expression in ASC on contact with EC. Although transforming growth factor-β and activin A were individually sufficient to initiate expression of smooth muscle cell antigens in ASC, only activin A IgG blocked the effect of EC-ASC conditioned media. Although transforming growth factor-β was able to induce activin A expression in ASC, in cocultures this induction was transforming growth factor-β independent. In EC-ASC cocultures, activin A IgG or ALK4/5/7 receptor inhibitors blocked expression of α-smooth muscle actin in ASC in the absence of direct ECcord contact, but this inhibition was circumvented in ASC by direct EC contact. Conclusions: EC initiate a smooth muscle cell differentiation program in adjacent ASC and propagate this differentiation in distant ASC by induction of activin A expression. (Circ Res. 2014;115:800-809.) © 2014 American Heart Association, Inc. Source

Dai J.,Vanderbilt University | Dai J.,Indiana University Bloomington | Dai J.,Indiana Center for Vascular Biology and Medicine | Krasnow R.E.,SRI International | And 3 more authors.

Background:Due to the paucity of direct evidence, we aimed to evaluate whether the association between postload plasma glucose levels (ppGlucose) and long-term risk of mortality from coronary heart disease was independent of or attributable to genes and common environment.Methods and Findings:From the prospective National Heart, Lung, and Blood Institute (NHLBI) Twin Study, we included 903 middle-aged male twins, who were nondiabetic, free of coronary heart disease at baseline (1969-1973), and followed for up to 38 years for coronary heart, cardiovascular, and all-cause mortality. Frailty survival models were used to estimate hazard ratio (HR) for various associations: overall (equivalent to singleton population association), within-pair (controlling for genes and environment common to co-twins), and between-pair association (reflecting influences of common factors). Overall associations were statistically significant for coronary heart and cardiovascular but not all-cause deaths after controlling for known risk factors. The associations were not statistically significant in within-pair analyses. The within-pair association was not statistically different by zygosity for specific and all-cause death risk. After the full adjustment for known risk factors, HR (95% confidence interval) for within-pair association was 1.07 (0.90, 1.28), 1.06 (0.94, 1.19), and 0.99 (0.94, 1.05) for coronary heart, cardiovascular, and all-cause mortality, respectively. The fully adjusted between-pair associations were statistically significant for specific and all-cause death risk: a 50 mg/dL increase in the mean value of ppGlucose for a twin pair was associated with a raised death risk [HR (95% confidence interval) 1.15 (1.02, 1.30), 1.10 (1.02, 1.20), and 1.05 (1.01, 1.09) for coronary heart, cardiovascular, and all-cause mortality, respectively]. Between-pair association was significant in dizygotic but not in monozygotic twins.Conclusion:The positive association between ppGlucose and long-term coronary heart mortality risk is largely explained by factors shared between co-twins, including familial factors; however, within-pair effects cannot be absolutely excluded. © 2013 Dai et al. Source

Hong S.J.,Krannert Institute of Cardiology | Hong S.J.,Indiana Center for Vascular Biology and Medicine | Hong S.J.,Indiana University | Hong S.J.,Korea University | And 7 more authors.
Current Opinion in Organ Transplantation

Purpose of review: Adipose-derived stem cells (ASCs) are readily available from autologous adipose tissue and have been demonstrated to provide significant potential for tissue rescue from, or repair of, damage in multiple animal models. These include models of myocardial infarction, heart failure, hind limb ischemia, and inflammatory conditions. Early clinical studies have now extended testing of the effects of ASC into patients. This review highlights some of the key reports underlining the potential of ASCs, focusing particularly on diseases involving the cardiovascular system, vascular growth, and tissue repair. Recent findings: Clinical applications of ASCs have begun to show early safety results and promising possibility of efficacy in patients with a range of diseases, including acute myocardial infarction, peripheral vascular disease, and soft and bony tissue defects including cranial bone loss, Crohn's-related fistula, and skin wounds. These effects are importantly based on the secretion of trophic and survival factors by these cells and by their participations in the growth and remodeling of blood vessels. These results suggest that ASCs could be a valuable therapeutic option in vascular growth and tissue repair in various clinical settings. Summary: ASCs may ultimately represent a valuable therapeutic option in tissue rescue and repair based on their ready availability, proangiogenesis and antiapoptotic factor secretion, immunomodulatory effects, and capacity for multilineage differentiation and ready expansion. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

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