Citations

ABSTRACT Background Renal artery stenosis (RAS) is an important cause of chronic kidney disease and secondary hypertension. In animal models, renal ischemia leads to downregulation of growth factor expression and loss of intrarenal microcirculation. However, little is known about the sequelae of large-vessel occlusive disease on the microcirculation within human kidneys. Method This study included five patients who underwent nephrectomy due to renovascular occlusion and seven nonstenotic discarded donor kidneys (four deceased donors). Micro-computed tomography was performed to assess microvascular spatial densities and tortuosity, an index of microvascular immaturity. Renal protein expression, gene expression and histology were studied in vitro using immunoblotting, polymerase chain reaction and staining. Results RAS demonstrated a loss of medium-sized vessels (0.2–0.3 mm) compared with donor kidneys (P = 0.037) and increased microvascular tortuosity. RAS kidneys had greater protein expression of angiopoietin-1, hypoxia-inducible factor-1α and thrombospondin-1 but lower protein expression of vascular endothelial growth factor (VEGF) than donor kidneys. Renal fibrosis, loss of peritubular capillaries (PTCs) and pericyte detachment were greater in RAS, yet they had more newly formed PTCs than donor kidneys. Therefore, our study quantified significant microvascular remodeling in the poststenotic human kidney. RAS induced renal microvascular loss, vascular remodeling and fibrosis. Despite downregulated VEGF, stenotic kidneys upregulated compensatory angiogenic pathways related to angiopoietin-1. Conclusions These observations underscore the nature of human RAS as a microvascular disease distal to main vessel stenosis and support therapeutic strategies directly targeting the poststenotic kidney microcirculation in patients with RAS.

Background: Digital health applications are increasingly ubiquitous, however the effectiveness remains mixed. Using a large working age cohort we sought to evaluate use of a digital health intervention (DHI) in people with uncontrolled hypertension and their changes in blood pressure control. Methods: We analyzed usage of DHI and change in blood pressure control and other CVD risk factors over one year in 9,724 participants of a work health program across 81 organizations in 42 states. Patients were selected from a larger cohort based on a previous ICD-9 diagnosis of hypertension. Patients with uncontrolled hypertension, systolic blood pressure (SBP) greater than 140 mmHg, at the initial visit were included. Application users, defined as at least one login, were compared to non-users. Changes in blood pressure, weight, and lipids were compared at one year. Results: Users and non-users were similar in age, weight, blood pressure and lipids at baseline, though users were more likely to be female. At one year users had 16.44 mmHg reduction in SBP and 7.16 mmHg reduction in diastolic blood pressure (DBP), both statistically significantly more than non-users (Table 1). Both users and non-users had an improvement in LDL from baseline, while non-users also had an improvement in BMI and TG from baseline. Discussion: These results show that the use of a DHI is associated with improved systolic and diastolic blood pressure control compared to a workplace health program alone.

Introduction: The metabolic syndrome (MetS) leads to cardiac vascular injury, which may reflect in increased retention of endothelial progenitor cells (EPC). Coronary endothelial cell (EC) mitochondria partly regulate vascular function and structure. We hypothesized that chronic mitoprotection would preserve EC mitochondria and attenuate coronary vascular injury and dysfunction in swine MetS. Methods: Pigs were studied after 16 weeks of diet-induced MetS, MetS treated for the last 4 weeks with the mitochondria-targeted peptide elamipretide (ELAM, 0.1mg/kg SC q.d), and lean controls (n=6 each). Coronary artery and sinus blood samples were collected. EC mitochondrial density (electron microscopy), endothelial nitric oxide (eNOS) immunoreactivity (staining), myocardial microvascular density (3D micro-CT), and coronary endothelial function (organ bath) were assessed ex-vivo. The number and arteriovenous gradient of CD34+/KDR+ EPC was calculated by FACS (a negative gradient indicating EPC retention). Results: MetS and MetS+ELAM pigs developed similar MetS (obesity, hyperlipidemia, insulin resistance, and hypertension). EC mitochondrial density decreased in MetS compared to lean, but normalized in MetS+ELAM. ELAM also improved eNOS immunoreactivity, subendocardial microvascular density, and coronary endothelial function. ELAM-induced vasculoprotection was reflected in decreased coronary retention of EPCs. Conclusions: These observations underscore the role of mitochondria in regulating the cardiac circulation in experimental MetS, and the benefits of mitoprotection to preserve EC myocardial microvascular integrity.

Background: Ischemic event rates are low after percutaneous coronary intervention (PCI), conversely second generation P2Y12 inhibitors increase bleeding therefore identifying patients at risk to enable precision in prescribing dual anti-platelet therapy (DAPT) is of clinical interest. Prior machine-learning predictive analyses have been limited by use of older generation stents and lack of genetic data. We utilized clinical and genetic data of patients with new generation stents enrolled in TAILOR-PCI, a 40-center international trial to predict ischemic events after PCI. Methods: There were 4398 eligible post PCI patients with acute coronary syndromes or stable coronary artery disease who were randomly split into training (n=3299) and validation (n=1099) cohorts. The primary endpoint comprising of cardiovascular death, myocardial infarction, stroke, or stent thrombosis within 12 months of PCI was predicted with patient characteristics prior to hospital discharge. First, random forests were used for feature selection with 1,000 bootstraps comprising equal numbers of those with and without ischemic events to minimize the bias of sample imbalance. Features were selected by a consensus on variable-importance over bootstraps. Second, using these features in the training cohort, support vector machines (SVM) with a polynomial kernel was trained with repeated 5-fold cross validation to choose a model with highest area under the receiver operating characteristic curve (AUC) which was then used to predict ischemic events in the validation cohort. Results: The primary endpoint occurred in 2.4% of patients. Using 89 clinical and genetic variables in the random-forest feature selection step, variable importance-based consensus identified 50 top predictors. These 50 predictors achieved AUC=0.703 in the SVM training cohort and AUC=0.744 (specificity=0.84; sensitivity =0.43) in the SVM validation cohort. Conclusions: Machine learning methods using baseline clinical and genetic data enables prediction of infrequent ischemic events in post PCI patients receiving new generation stents. The role of such artificial intelligence algorithms in individualization of DAPT by identifying high or low risk patients needs to be explored.

Introduction: Coronary vasomotor response is different between males and females. Overall, females have lower coronary flow reserve (CFR) than males due to higher baseline coronary flow than males. Hypothesis: Sex has an essential role in the interaction between age and CFR. Methods: We included 668 patients with nonobstructive coronary artery disease who underwent invasive coronary vasoreactivity testing using intracoronary incremental doses of adenosine (18-72 μg). Changes in CFR (hyperemic flow velocity/baseline flow velocity) with aging were separately analyzed between males (N=207, mean age 53±13 years) and females (N=461, mean age 54±12 years). We further divided patients by age of 53 which is average age of menopause. Results: In males, CFR decreased with aging in younger patients <53 years and tended to decrease in older male patients (all ages [N=207]: r=-0.33, P <0.0001; <53 years [N=99]: r=-0.27, P =0.01; ≥53 years [N=108]: r=-0.17, P =0.07) ( Figure A ). In contrast, CFR did not decrease with aging in younger females <53 years, whereas there was a significant negative correlation between CFR and age in older females ≥53 years (all ages [N=461]: r=-0.15, P =0.001; <53 years [N=211]: r=-0.006, P =0.39; ≥53 years [N=250]: r=-0.25, P <0.0001) ( Figure B ). Baseline microvascular resistance (BMR) was similar between younger and older males ( P =0.30), whereas older females had higher baseline BMR than younger females ( P <0.0001) ( Figure C ). Conclusions: CFR decreased with aging in males and older females, but not in younger females, potentially highlighting the role of protective hormonal differences in maintaining low baseline coronary tone in younger females.

Background: The expansion of adipose mass requires adipocyte precursor cells that originate from multipotent mesenchymal stem cells (MSC). The inflammatory milieu in obesity often involves high levels of tumor necrosis factor (TNF)-α in adipose tissue, but whether this affects MSC function remains unknown. We tested the hypothesis that microenvironmental changes during the evolution of obesity affect MSC function, which may in turn promote obesity. Methods: Domestic pigs were fed with an adipogenic (n=7) or normal (n=7) diet for 16 weeks. Abdominal adipose tissue biopsies were collected at 8, 12, and 16 weeks for histology and MSC culture. Adipose tissue inflammation and MSC levels were evaluated in situ using immunohistochemistry staining for TNF-α, CD34, and Von Willebrand factor (vWF). The adipogenic propensity of MSC was tested in vitro using appropriate differentiation media, with or without supplementation of TNF-α or anti-TNF-α antibody for 3 weeks. Results: Obese pigs had increased body weight and abdominal fat mass (by CT) compared with lean pigs. TNF-α expression in adipose tissue (Figure 1A) was upregulated in obese pigs at 12 and 16 weeks, accompanied by increased numbers of MSC (CD34 + /vWF - ) at 16 weeks. In vitro, MSC derived from obese adipose tissue at 16weeks showed enhanced adipogenesis, which was abolished by anti-TNF-α treatment. Similarly, in lean MSC TNF-α treatment enhanced adipogenesis (Figure 1B). Conclusion: Obesity-induced adipose tissue inflammation may stimulate MSC differentiation into adipocytes, which further increase the adipose tissue mass. Our results support development of anti-inflammatory strategies for obesity management.

Background: Coronary endothelial dysfunction(CED) may reflect loss of vascular integrity and permeability. We aimed to test the hypothesis that CED may be associated with increased risk of bleeding events. Methods: Coronary vascular reactivity was evaluated in 444 patients with non-obstructive coronary arteries by administration of intracoronary acetylcholine during angiography. CED was defined as a ≤ 50% increase in coronary blood flow (CBF) from baseline in response to maximal dose of acetylcholine. After a median follow-up of 7 years, patients were assessed for the occurrence of any significant bleeding events. Results: Of 444 patients, 70.7% (314) were female. Average age was 52.3 years. Of 252 patients with CED, 7.9% (20) developed bleeding events compared to 2.1% (4 of 192) without CED (p=0.004). Patients who developed bleeding events had a lower percent change in CBF vs. those who did not median: (IQR) 14.1 (-28.1, 98.7) vs. 40.0 (-11.0, 103.5); p=0.03 (Figure 1). CED was significantly associated with the development of bleeding in univariate analysis(p=0.004, relative risk: 3.81 CI, 1.32, 10.96). In multivariate analysis CED was an independent predictor of development of bleeding (p=0.01) Conclusions: CED is associated with increased risk of bleeding events. This can be explained by the altered vascular function that is inherent to CED. This study underscores the systemic involvement of the endothelium in vascular disease, and the concept of the ‘vulnerable patient’.

Background: Atherosclerosis is an inflammatory disease with T cells and macrophages as the leading plaque cell populations. The immunoproteasome (IP) influences T cell survival and differentiation but its impact on macrophage survival and differentiation remains unknown, which was the objective of this study. Methods: Murine monocyte/macrophage Raw264.7 cells were stimulated by IFN-gamma (20 ng/mL) plus LPS (10pg/mL) or IL-4 (20 ng/mL) for 18 hours to induce M1 and M2 macrophages, and these differentiated macrophages were then re-exposed to IFN- gamma and IL-4 for another 24 hours, without and with IP subunit beta 5i inhibition by siRNA or Onx0914. Nitric oxide synthase and arginase activity served as differentiation markers (analyzed by enzymatic assays) as did the cytokine/chemokine profile (analyzed by antibody arrays). Cell viability was tested by an XTT assay and apoptosis by TUNEL FACS. Results: IP beta5i knockout/inhibition did not influence M1 and M2 macrophage differentiation. Also, no significant differences in apoptosis were observed between RAW264.7 cells treated with and without beta 5i inhibitor during macrophage differentiation. With re-exposure to IFN- gamma and IL-4, however, there was more apoptosis and less survival of differentiated M1 macrophages with beta5i inhibition. Conversely, beta 5i inhibition achieved less apoptosis and more survival of differentiated M2 macrophages when switching IL-4- to IFN-gamma-stimulating conditions. Conclusions: IP inhibition does not influence macrophage differentiation but survival of differentiated macrophages of potential significance for the atherosclerotic disease process.

Background A growing body of evidence links coronary artery atherosclerosis and calcification to osteoporosis in women. Coronary endothelial dysfunction (CED) is associated with adverse cardiovascular events. We aimed to study the association of CED and development of osteoporosis. Methods Coronary vascular reactivity was evaluated in 225 women, greater than age 50, with non-obstructive coronary arteries, by administration of intracoronary acetylcholine during diagnostic angiography. CED was defined as <50% increase in coronary blood flow (CBF) from baseline in response to maximal dose. After a median follow-up of 7 years, patients were assessed by a questionnaire for development of osteoporosis. Results The average age of the cohort was 60 years. Of 225 women, 60% (135) had CED. 18.2% (41 of 225 women) developed osteoporosis during follow-up. Women with CED were twice more likely to develop osteoporosis vs. women without CED (23% vs. 11.1%, p=0.024). Women who developed osteoporosis compared to those who did not had a markedly lower response (% change) in CBF: median (IQR)-4.3 (-28.3, 51.7) vs. 39.9 (-8.2, 106.0), p=0.007. In univariate analysis, CED was significantly associated with development of osteoporosis (p=0.024, relative risk 2.07, 95% CI: 1.07, 4.00). Multivariate analysis indicated CED as an independent predictor of osteoporosis (p=0.04). Discussion Endothelial dysfunction may account for or share similar mechanisms with development of osteoporosis in cardiac patients.