Urocortin-2 (UCn2) peptide infusion increases cardiac function in patients with heart failure, but chronic peptide infusion is cumbersome, costly, and provides only short-term benefits. Gene transfer would circumvent these shortcomings. Here we ask whether a single intravenous injection of adeno-associated virus type 8 encoding murine urocortin-2 (AAV8.UCn2) could provide long-term elevation in plasma UCn2 levels and increased left ventricular (LV) function. Normal mice received AAV8.UCn2 (5 · 10 11 genome copies, intravenous). Plasma UCn2 increased 15-fold 6 weeks and > 11-fold 7 months after delivery. AAV8 DNA and UCn2 mRNA expression was persistent in LV and liver up to 7 months after a single intravenous injection of AAV8.UCn2. Physiological studies conducted both in situ and ex vivo showed increases in LV + dP/dt and in LV -dP/dt, findings that endured unchanged for 7 months. SERCA2a mRNA and protein expression was increased in LV samples and Ca 2 + transient studies showed an increased rate of Ca 2 + decline in cardiac myocytes from mice that had received UCn2 gene transfer. We conclude that a single intravenous injection of AAV8.UCn2 increases plasma UCn2 and increases LV systolic and diastolic function for at least 7 months. The simplicity of intravenous injection of a long-term expression vector encoding a gene with paracrine activity to increase cardiac function is a potentially attractive strategy in clinical settings. Future studies will determine the usefulness of this approach in the treatment of heart failure.

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Urocortin-2 (UCn2) peptide infusion increases cardiac function in patients with heart failure, but chronic peptide infusion is cumbersome, is costly, and provides only short-term benefits. Gene transfer would circumvent these shortcomings. We previously showed that a single intravenous (IV) injection of AAV8.UCn2 increases plasma UCn2 and left ventricular (LV) systolic and diastolic function for at least 7 months in normal mice. Here we test the hypothesis that IV delivery of AAV8.UCn2 increases function of the failing heart. Myocardial infarction (MI, by coronary ligation) was used to induce heart failure, which was assessed by echocardiography 3 weeks after MI. Mice with LV ejection fraction (EF) <25% received IV delivery of AAV8.UCn2 (5×1011 gc) or saline, and 5 weeks later echocardiography showed increased LV EF in mice that received UCn2 gene transfer (p=0.01). In vivo physiological studies showed a 2-fold increase in peak rate of LV pressure development (LV +dP/dt; p<0.0001) and a 1.6-fold increase in peak rate of LV pressure decay (LV −dP/dt; p=0.0007), indicating increased LV systolic and diastolic function in treated mice. UCn2 gene transfer was associated with increased peak systolic Ca2+ transient amplitude and rate of Ca2+ decline and increased SERCA2a expression. In addition, UCn2 gene transfer reduced Thr286 phosphorylation of Cam kinase II, and increased expression of cardiac myosin light chain kinase, findings that would be anticipated to increase function of the failing heart. We conclude that a single IV injection of AAV8.UCn2 increases function of the failing heart. The simplicity of IV injection of a vector encoding a gene with beneficial paracrine effects to increase cardiac function is an attractive potential clinical strategy.

Background The pathophysiology of increased severity of erectile dysfunction in men with diabetes and their poor response to oral pharmacotherapy are unclear. Defective vascular endothelium and consequent impairment in the formation and action of nitric oxide (NO) are implicated as potential mechanisms. Endothelial NO synthase, critical for NO generation, is localized to caveolae, plasma membrane lipid rafts enriched in structural proteins, and caveolins. Type 2 diabetes mellitus (T2DM)-induced changes in caveolin expression are recognized to play a role in cardiovascular dysfunction. Aims To evaluate DM-related changes to male erectile tissue in a mouse model that closely resembles human T2DM and study the specific role of caveolins in penile blood flow and microvascular perfusion using mice lacking caveolin (Cav)-1 or Cav-3. Methods We used wild-type C57BL6 (control) and Cav-1 and Cav-3 knockout (KO) male mice. T2DM was induced by streptozotocin followed by a high-fat diet for 4 months. Penile expressions of Cav-1, Cav-3, and endothelial NO synthase were determined by western blot, and phosphodiesterase type 5 activity was measured using [3H] cyclic guanosine monophosphate as a substrate. For hemodynamic studies, Cav-1 and Cav-3 KO mice were anesthetized, and penile blood flow (peak systolic velocity and end-diastolic velocity; millimeters per second) was determined using a high-frequency and high-resolution digital imaging color Doppler system. Penile tissue microcirculatory blood perfusion (arbitrary perfusion units) was measured using a novel PeriCam PSI system. Outcomes Penile erectile tissues were harvested for histologic studies to assess Cav-1, Cav-3, and endothelial NO synthase expression, phosphodiesterase type 5 activity, and blood flow, and perfusion measurements were assessed for hemodynamic studies before and after an intracavernosal injection of prostaglandin E1 (50 ng). Results In T2DM mice, decreased Cav-1 and Cav-3 penile protein expression and increased phosphodiesterase type 5 activity were observed. Decreased response to prostaglandin E1 in peak systolic velocity (33 ± 4 mm/s in Cav-1 KO mice vs 62 ± 5 mm/s in control mice) and perfusion (146 ± 12 AU in Cav-1 KO mice vs 256 ± 12 AU in control mice) was observed. Hemodynamic changes in Cav-3 KO mice were insignificant. Clinical Translation Our findings provide novel mechanistic insights into erectile dysfunction severity and poor pharmacotherapy that could have potential application to patients with T2DM. Strengths and Limitations Use of KO mice and novel hemodynamic techniques are the strengths. A limitation is the lack of direct evaluation of penile hemodynamics in T2DM mice. Conclusion Altered penile Cav-1 expression in T2DM mice and impaired penile hemodynamics in Cav-1 KO mice suggests a regulatory role for Cav-1 in DM-related erectile dysfunction.

Aim: Circulating aromatic amino acids and branched chain amino acids (BCAA) predict new-onset type 2 diabetes (T2DM). Metformin reduces the risk of developing T2DM. We investigated whether metformin therapy alters amino acid (AA) concentrations. Methods: In the CAMERA study, individuals without diabetes but with coronary heart disease were randomised to metformin (n=86) or placebo (n=87). Plasma samples were obtained at 0, 6, 12 and 18 months and analysed using quantitative NMR spectroscopy. Eight AAs (three BCAAs [isoleucine, leucine, valine], two aromatic AAs [tyrosine, phenylalanine] and three other AAs [alanine, glutamine, histidine]) were quantified. Repeated-measures model analysis was applied and associations with changes in weight, fat mass and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) were also investigated. Results: Over 18 months, metformin reduced HOMA-IR, weight and fat mass compared to placebo though not carotid intimamedia thickness, the primary outcome. Tyrosine (-9.6% [95% CI À13.5% to À5.7%, p < 0.0001]) and phenylalanine (À4.0% [À7.7% to À0.4%, p=0.03]) decreased while alanine (16.5% [8.5% to 24.5%, p < 0.0001)) and histidine (5.8% [0.1% to 11.5%, p=0.045]) increased in metformin-treated patients compared to placebo in repeated-measures analysis. No changes were observed in circulating BCAAs or glutamine. The decrease in tyrosine was associated with decreases in both HOMA-IR and weight. Changes in phenylalanine, alanine and histidine were not associated with changes in HOMA-IR, body weight or fat mass. Conclusion: Treatment with metformin over 18 months reduced aromatic AAs and increased alanine and histidine. Whether these changes are causally linked to the reduction in new-onset T2DM on metformin requires further study. A34 (P187)High intensity intermittent training improves cardiac function and reduces liver fat in adults with Type 2 diabetes: an MRI/S study Aims: Heart disease is the leading cause of morbidity and mortality in Type 2 diabetes. This study assessed high intensity intermittent training (HIIT) as a potential therapeutic tool to moderate cardiac risk and reduce liver fat in this patient group. Methods: Twenty-three adults with Type 2 diabetes (age 60 AE 9 years) were randomised to 12 weeks of HIIT (treatment, n=12) or standard care (controls, n=11). Cardiac structure and function were measured by 3.0 T magnetic resonance imaging and two-dimensional tagging. Liver fat was determined by 1 H magnetic resonance spectroscopy. Results: HIIT improved cardiac structure (left ventricular mass 104 AE 17 to 116 AE 20g vs 107 AE 25 to 105 AE 25g, p < 0.05; end-diastolic blood volume 118 AE 30 to 126 AE 30ml vs 129 AE 28 to 122 AE 28ml, p < 0.05) and systolic function (stroke volume 76 AE 16 to 87 AE 19ml vs 79 AE 14 to 75 AE 15ml, p < 0.05) compared to controls. Early diastolic filling rates increased (241 AE 84 to 299 AE 89ml/s vs 250 AE 44 to 251 AE 47ml/s, p < 0.05) and peak torsion decreased (8.1 AE 1.8 to 6.9 AE 1.6°v s 7.1 AE 2.2 to 7.6 AE 1.9°, p < 0.05). HIIT re...

were processed for qPCR expression of SDF1, CXCR4, CXCR7, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), glial-derived neurotrophic factor (GDNF), neuronal NOS, and tyrosine hydroxylase (TH).RESULTS: Significant (p<0.05) increases in neurite length with SDF1 500ng/mL treatment compared to paired controls were seen at 48 (746AE45 vs. 575AE34 uM) and 72 hours (1045AE46 vs. 739AE34 uM). This effect was abrogated with AMD3100 CXCR4 blockade (771AE97, 72 hours, p¼0.7). SDF1 125ng/mL treatment trended in improved nerve regeneration at 72 hours (990AE86, p¼0.23). SDF1 treatment increased neurotrophin expression in a dose-dependent manner. Compared to controls, SDF1 treatment with 125ng/mL and 500ng/mL significantly (p<0.05) increased expression of NGF (1.7 and 2.1 fold, respectively) and BDNF (both 1.7 fold). Treatment with 500ng/mL SDF1 increased GDNF expression compared to controls (2.1 fold p<0.05), whereas 125ng/mL did not. TH expression was decreased by 33% with SDF1 125ng/mL treatment and 57% with SDF1 500ng/mL treatment. nNOS expression was not affected by SDF1 treatment. SDF1 125ng/mL and 500ng/mL treatment increased SDF1 expression of the MPGs by 1.8 and 3.4 fold compared to controls, respectively (both p<0.05). qPCR expression of the above targeted genes were similar between controls and combined SDF1 500mg/mL+AMD3100 treatment. Combined treatment resulted in a 44% (p<0.01) elevation in CXCR4 expression, suggesting compensatory upregulation in the setting of receptor blockade.CONCLUSIONS: SDF1 treatment facilitates axonal regeneration from the MPG by upregulating neurotrophin pathways and utilizing positive feedback to increase SDF1 expression, which was prevented by CXCR4 blockade. Greater SDF1 concentration increased gene expression and neurite length suggesting a dose response.

The inbred mouse strain C57BL/6 is highly suitable and commonly used for the generation of transgenic mice as tools in dissecting biological processes and diseases. However, this parent line is available from a variety of sources with different sub‐strains. We examined male C57BL/6J mice from the Jackson Laboratory (n=29) and male C57BL/6NHsd from the Harlan Laboratories (n=36) in the setting of transverse aortic constriction (TAC), which is a common interventional procedure for studying pressure‐overload in hearts. Under anesthesia, the aortic arch between the innominate and the left carotid artery was constricted to 0.413 mm (27 ga needle) with a 7‐0 silk suture. Survival was monitored for 3 wks, and subsequently left ventricular function was assessed with a 1.4F Millar pressure transducer. Three wks after TAC, the survival rate was 50% for the C57BL/6NHsd and 79% survived for the C57BL/6J (Top Figure). A significant decline of 1058 mmHg/s (21%) in cardiac contractility (Bottom Figure) and 1228 mmHg/s (22%) in the rate of decay was found in C57BL/NHsd mice.ConclusionThis study demonstrates phenotypic differences in viability and cardiac performance in response to TAC for these two sub‐strains. Therefore, it is imperative to carefully consider the appropriate line for the design of transgenic mice.

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