MicroRNA-126 mimic administration accelerates vascular perfusion recovery and angiogenesis in a hind limb ischemia model

Background Peripheral arterial disease caused mainly by atherosclerosis portent significant morbidity, adverse prognosis and mortality, with localized treatment approaches aiming at symptom alleviation and improvement of circulation. Recently, scientific interest has been shifted towards epigenomics, with microRNAs appearing as a future therapeutic target in ischemic cardiovascular diseases due to their potential in regulating angiogenesis. Purpose We investigated the pro-angiogenic effect of miRNA-126 mimic in an in vivo model of hind limb ischemia. Methods Ten-week-old male C57Bl/6 mice (n=20) were subjected to left femoral artery ligation and were treated with microRNA-126 mimic at a dose of 5mg/kg (Group A, n=10) or 0.2ml normal saline (Group B, n=10) on days 1, 3 and 7. Laser Doppler imaging was performed to verify successful ligation on day 0 and to evaluate differences in the ischemic-to-normal (I/N) hind limb perfusion ratio on day 7 and 28. Muscle tissue expression of microRNA-126 and vascular endothelial growth factor (VEGF) was determined via PCR. Results Following microRNA-126 mimic administration in Group A subjects, we noted a qualitative and quantitative stepwise increase in I/N hind limb perfusion ratio [Day 0: 0.354 (0.276, 0.455) vs. Day 8: 0.775 (0.700, 0.844) vs. Day 28: 0.681 (0.660, 0.896), p=0.001] (Figure 1, Panels A and B). In Group B a stepwise increase of lesser magnitude was observed in I/N hind limb perfusion ratio [Day 0: 0.267 (0.164, 0.383) vs. Day 8: 0.400 (0.338, 0.418) vs. Day 28: 0.539 (0.483, 0.603), p=0.074]. Importantly, over time changes of I/N hind limb perfusion ratio were significantly higher in group A compared to group B (p for interaction=0.005) (Figure 1, Panel B). Muscle tissue expression of microRNA-126 in the ischemic hind limb of Group A was 350-fold lower compared to the ischemic hind limb of Group B (p<0.001) (Figure 1, Panel C). A higher expression (14.2-fold) of VEGF in the ischemic hind limb of microRNA-126-treated mice compared to that of control group was detected (p<0.001) (Figure 1, Panel C). A statistically significant negative correlation was noted between microRNA-126 and VEGF tissue expression levels in the ischemic limbs of both Group A and B subjects whereas no correlation between microRNA-126 and VEGF was observed in the non-ischemic hind limbs of the entire study population (Figure 1, Panel D). Conclusion MicroRNA-126 mimic delivery in the ischemic hind limb of mice can accelerate vascular perfusion recovery via angiogenesis, which is mediated by VEGF expression. FUNDunding Acknowledgement Type of funding sources: None. Figure 1

Abstract P247: Elastin Insufficiency Impairs Renal Hemodynamics And Accelerates Aging-associated Structural And Functional Remodeling Of Preglomerular Arterioles

Elastin degradation and fragmentation are hallmarks of arterial stiffness and renal dysfunction associated with aging. However, it is unclear whether elastin insufficiency contributes to the changes in the structure and function of the resistance vasculature of the kidney during aging. Here we determined how increased vascular stiffness due to elastin insufficiency alters renal hemodynamics and mechanical properties of preglomerular arterioles. We assessed renal hemodynamics under anesthesia in 14-16-month-old female wild type (WT) and elastin heterozygous ( Eln +/- ) mice. Renal autoregulation was assessed by a stepwise increase in renal perfusion pressure (RPP) by simultaneously occluding the superior mesenteric and celiac arteries. Myogenic constriction and arterial stiffness were assessed by pressure myography of isolated renal interlobar arteries. Baseline renal vascular resistance (RVR) was elevated in Eln +/- mice (13.8 ± 2.9 vs 11.2 ± 1.4 mmHg/μL/min/g left kidney weight), while systolic blood pressure (SBP; 75.1 ± 7.4 vs 91 ± 4.2mmHg), renal blood flow (RBF; 6.3 ± 1.2 vs 7.4 ± 1.7 μL/min/g left kidney weight), renal plasma flow (RPF; 3.4 ± 0.8 vs 5 ± 1.2 mL/min/g/ left kidney weight) and urine flow rate, all trended lower in Eln +/- mice compared to WT mice. Glomerular filtration rate (GFR) and filtration fraction (FF) were similar between the two groups. A stepwise increase in RPP caused a slower decline and rise in RBF and RVR, respectively, in Eln +/- relative to WT mice. The maximal changes in RBF (5 ± 1.1 vs 4.7 ± 0.8 μL/min/g left kidney weight), RVR (17.6 ± 7.3 vs 22.5 ± 2.1 mmHg/μL/min/g left kidney weight), urine flow rate,GFR, and FF were less robust in Eln +/- mice. RPF decreased in WT mice in response to raising RPP, whereas it remained unchanged in Eln +/- mice. Myogenic response and increases in elastic modulus and wall tension following stepwise changes in intraluminal pressure were all augmented in interlobar arteries from Eln +/- relative to WT mice. However, there was no difference in kidney weight/tibia length ratio between the two genotypes. We conclude that elastin insufficiency impairs renal hemodynamics by exacerbating age associated increase in vascular stiffness.

The Effect of MicroRNA-126 Mimic Administration on Vascular Perfusion Recovery in an Animal Model of Hind Limb Ischemia

Background: MicroRNAs have been linked to angiogenesis and could prove to be valuable future therapeutic targets in ischemic cardiovascular diseases.Methods: Ten-week-old male C57Bl/6 mice were subjected to left femoral artery ligation and were treated with microRNA-126 mimic at a dose of 5 mg/kg (Group A, n = 10) or 5 mg/kg microRNA mimic negative control (Group B, n = 10) on days 1, 3, and 7. Laser Doppler imaging was performed to verify successful ligation on day 0 and to evaluate differences in the ischemic-to-normal (I/N) hind limb perfusion ratio on day 28. Muscle tissue expression of microRNA-126 and vascular endothelial growth factor (VEGF) was determined via PCR.Results: Following microRNA-126 mimic administration in Group A subjects, we noted a stepwise increase in I/N hind limb perfusion ratio (Day 0: 0.364 ± 0.032 vs. Day 8: 0.788 ± 0.049 vs. Day 28: 0.750 ± 0.039, p = 0.001). In Group B a stepwise increase in I/N hind limb perfusion ratio was observed (Day 0: 0.272 ± 0.057 vs. Day 8: 0.382 ± 0.020 vs. Day 28: 0.542 ± 0.028, p = 0.074). Muscle tissue expression of microRNA-126 in the ischemic hind limb of Group A was 350-fold lower compared to the ischemic hind limb of Group B (p < 0.001). A higher expression (14.2-fold) of VEGF in the ischemic hind limb of microRNA-126-treated mice compared to that of control group was detected (p < 0.001). A statistically significant negative correlation was noted between microRNA-126 and VEGF tissue expression levels in the ischemic limbs of the entire study population.Conclusion: MicroRNA-126 delivery in the ischemic hind limb of mice improved vascular perfusion with VEGF upregulation.

How Enzymes, Proteins, and Antibodies Recognize Extended DNAs; General Regularities

X-ray analysis cannot provide quantitative estimates of the relative contribution of non-specific, specific, strong, and weak contacts of extended DNA molecules to their total affinity for enzymes and proteins. The interaction of different enzymes and proteins with long DNA and RNA at the quantitative molecular level can be successfully analyzed using the method of the stepwise increase in ligand complexity (SILC). The present review summarizes the data on stepwise increase in ligand complexity (SILC) analysis of nucleic acid recognition by various enzymes—replication, restriction, integration, topoisomerization, six different repair enzymes (uracil DNA glycosylase, Fpg protein from Escherichia coli, human 8-oxoguanine-DNA glycosylase, human apurinic/apyrimidinic endonuclease, RecA protein, and DNA-ligase), and five DNA-recognizing proteins (RNA helicase, human lactoferrin, alfa-lactalbumin, human blood albumin, and IgGs against DNA). The relative contributions of structural elements of DNA fragments “covered” by globules of enzymes and proteins to the total affinity of DNA have been evaluated. Thermodynamic and catalytic factors providing discrimination of unspecific and specific DNAs by these enzymes on the stages of primary complex formation following changes in enzymes and DNAs or RNAs conformations and direct processing of the catalysis of the reactions were found. General regularities of recognition of nucleic acid by DNA-dependent enzymes, proteins, and antibodies were established.

THE APPARATUS ARRANGEMENT AND REGIME PARAMETERS FOR ISOPRENE POLYMERIZATION PROCESS IN BULK

The stationary bed type regimes of apparatuses for catalytic isoprene polymerization process in bulk are investigated. If the polymerization process is performed with the bed height equal to 3 mm, the thermal apparatus regime is close to isothermic one. The increase of the bed height up to 6 mm makes the apparatus regime wide of the mark. To remove the lack there is proposed the regime providing the one time stepwise increase of the wall apparatus temperature. Due to proposed regime the apparatus efficiency makes gain while polymerization is performed up to incomplete conversions

Functional DSCT assessment of tricuspid regurgitation: AROA reproducibility and comparison with 3D TEE

Funding Acknowledgements Type of funding sources: None. onbehalf Minneapolis Heart Institute Foundation Background Tricuspid regurgitation (TR) assessment by echocardiography is often challenging. Functional dual-source CT (DSCT) with third-generation scanners allows accurate evaluation of leaflet anatomy and mobility. Purpose Investigate the reproducibility of tricuspid anatomical regurgitant orifice area (AROA) by DSCT, and its correlation with TR quantification by 3D TEE. Methods We evaluated patients with symptomatic TR referred for transcatheter tricuspid repair. DSCT (SOMATOM Force [Siemens, Erlangen, Germany]) and 3D TEE was performed on the same day as part of our institutional registry. DSCT scans were retrospective and ECG-gated, with a contrast protocol to enhance the right heart. The reproducibility of tricuspid AROA was assessed in 20 patients. The tricuspid AROA was compared with the TR severity (5-grade classification) and the 3D VCA by TEE (Panel 1). Results We included 60 patients (Table). The AROA had excellent intra and interobserver reliability (ICC 0.99 [0.97, 0.99] and 0.99 [0.96, 0.99]). We found a stepwise increase in tricuspid AROA from moderate to torrential TR (Panel 2A). Of 60 patients, 3D VCA was feasible in 39; in those, we found an excellent linear correlation of AROA and 3D VCA (Panel 2B). Conclusions Tricuspid AROA by DSCT was reproducible, showed a stepwise increase from moderate to massive TR and correlated with 3D VCA by TEE. Baseline Patient Characteristics All (n = 60) Age, years 82 ± 7 BSA, m2 1.8 ± 0.2 NYHA III-IV, n(%) 42 (70) Atrial Fibrilation 55 (91) Hypertension 44 (73) Pulmonary Hypertension 34 (56) Chronic Kidney Disease 25 (44) Coronary Artery Disease 17 (28) Chronic Lung Disease 14 (23) Permanent Pacemaker 13 (21) Diabetes Mellitus 10 (17) Mitral Valve Repair (MitraClip) 9 (15) Mitral Valve Replacement 7 (12) Mitral Valve Repair 3 (5) Aortic Valve Replacement 5 (8) Values are mean ± SD and n (%). BSA = body surface area. Abstract Figure. Panels

Abstract 16790: Myocardial Injury is an Independent Predictor of Mortality in Patients With COVID-19

Introduction: Recent reports on COVID-19 patients have shown that elevated troponin (Tn) levels on hospital admission are associated with adverse outcomes. However, no data exists on the predictive role of Tn kinetics parameters in COVID-19 patients. Aim: To analyze the incidence, clinical outcomes and predictors of Tn kinetics parameter, including rise/fall pattern and peak values, in a large cohort of COVID-19 hospitalized patients. Methods: All consecutive patients admitted to an urban tertiary-care health system between February and June 2020 with COVID-19 were included. Patients were grouped according to presence of myocardial injury defined as a high-sensitivity TnI level ≥0.1 ng/ml. A TnI level between 0.4-0.99 was defined as low positive range Tn elevation. Results: We included 5862 COVID-19 patients, 1558 (27%) of whom experienced myocardial injury. Advance age, male sex and higher comorbidity burden, including COPD, hypertension, CAD, atrial fibrillation, HF, CKD, and diabetes were more common in patients with myocardial injury. A total of 828/1558 (53.2%) of patients with myocardial injury died as compared to 634/4304 (14.7%) of those without (OR 6.57, 95% CI 5.76-7.48; p<0.001). After adjustment for baseline imbalances, myocardial injury remained an independent predictor of mortality (Adj.OR 5.26, 95% CI 4.57-6.05; p<0.001). Further stratification of patients into low positive range Tn elevation and myocardial injury groups showed a significant stepwise increase in mortality rates with increasing Tn values (Figure). Secondary endpoints, as shown in the Figure, occurred more frequently in patients with myocardial injury.Data on Tn kinetics parameters,such as rise/fall patterns,and associations with the outcomes will also be presented. Conclusions: Myocardial injury is an independent predictor of all-cause mortality in COVID-19 patients,with a stepwise increase in the risk of mortality reflecting increasing extent of myocardial damage.