Introduction: Erectile dysfunction (ED) worsens in men with diabetes. Human umbilical cord blood (HUCB), because of its widespread availability and low immunogenicity, is a valuable source for stem cell-based therapies. Aim: To determine the effect of intracavernous injection of HUCB mononuclear cells (MNCs) on ED in rats with diabetes induced by streptozotocin. Methods: Thirty adult male Sprague-Dawley rats were equally divided into three groups: (i) control, (ii) diabetes induced by streptozotocin (35 mg/kg intravenously for 8 weeks), and (iii) diabetic rats treated with MNCs (1 × 106 cells by intracavernosal injection). The HUCB-MNCs isolated by the Ficoll-Hypaque technique were obtained from eight healthy donors and administered to diabetic rats after 4 weeks. Main Outcome Measures: The ratio of intracavernosal pressure to mean arterial pressure ratio; the protein expression of endothelial and neuronal markers, such as von Willebrand factor, neuronal nitric oxide synthase, hypoxia-inducible factor-1α, and vascular endothelium growth factor; and the relative area of smooth muscle to collagen using western blotting and Masson trichrome staining were determined. Results: Diabetic rats demonstrated a significantly decreased ratio of intracavernosal pressure to mean arterial pressure (0.26 ± 0.04; P < .01) and treatment with MNCs restored erectile function in diabetic rats (0.67 ± 0.05) compared with control rats (0.56 ± 0.02). In bath studies, neurogenic relaxant and contractile responses were significantly decreased in diabetic cavernosal tissues, which were restored by treatment. The ratio of smooth muscle to collagen was partly recovered by treatment, whereas von Willebrand factor levels were not altered in any group. Neuronal nitric oxide synthase and vascular endothelium growth factor levels were decreased, which were not restored by treatment. Increased hypoxia-inducible factor-1α protein expression in the diabetic group was completely normalized in MNC-treated diabetic samples. Conclusion: These results suggest that HUCB-MNC treatment can enhance the recovery of erectile function and promote numerous activities such the contribution of the hypoxia-inducible factor-1α and von Willebrand factor pathway to the neurogenic erectile response of diabetic rats. HUCB-MNCs in the healing process could involve an adaptive regenerative response and appear to be a potential candidate for cell-based therapy in ED of men with diabetes. It is evident that HUCB could provide a realistic therapeutic modality for the treatment of diabetic ED.

The importance of chronic stimulation of β-adrenoceptors in the development of cardiac dysfunction is the rationale for the use of β-blockers in the treatment of heart failure. Nebivolol is a third-generation β-blocker, which has further properties including stimulation of endothelial nitric oxide synthase and/or β₃-adrenoceptors. The aim of this study was to investigate whether nebivolol has additional effects on β-adrenoceptor-mediated functional responses along with morphologic and molecular determinants of cardiac hypertrophy compared with those of metoprolol, a selective β₁-adrenoceptor blocker. Rats infused by isoprenaline (100 μg·kg⁻¹·day⁻¹, 14 days) were randomized into three groups according to the treatment with metoprolol (30 mg·kg⁻¹·day⁻¹), nebivolol (10 mg·kg⁻¹·day⁻¹), or placebo for 13 days starting on day 1 after implantation of minipump. Both metoprolol and nebivolol caused a similar reduction on heart rate. Nebivolol mediated a significant improvement on cardiac mass, coronary flow, mRNA expression levels of sarcoplasmic reticulum Ca²⁺ ATPase (SERCA2a) and atrial natriuretic peptide and phospholamban (PLN)/SERCA2a and phospho-PLN/PLN ratio compared with metoprolol and placebo. Nebivolol prevented the detrimental effects of isoprenaline infusion on isoprenaline (68% of control at 30 μM), BRL37344 (63% of control at 0.1 μM), and forskolin (64% of control at 1 μM) responses compared with metoprolol (isoprenaline, 34% of control; BRL37344, no response; forskolin, 26% of control) and placebo (isoprenaline, 33% of control; BRL37344, 28% of control; forskolin, 12% of control). Both β-blockers improved the changes in mRNA expressions of β₁- and β₃-adrenoceptors. Our results suggest that nebivolol partially protects the responsiveness of β-adrenoceptor signaling and the development of cardiac hypertrophy independent of its β₁-adrenoceptor blocking effect.

Clinical and experimental evidence suggest that increased rates of fatty acid oxidation in the myocardium result in impaired contractile function in both normal and diabetic hearts. Glucose utilization is decreased in type 1 diabetes, and fatty acid oxidation dominates for energy production at the expense of an increase in oxygen requirement. The objective of this study was to examine the effect of chronic treatment with trimetazidine (TMZ) on cardiac mechanical function and fatty acid oxidation in streptozocin (STZ)-diabetic rats. Spontaneously beating hearts from male Sprague–Dawley rats were subjected to a 60-minute aerobic perfusion period with a recirculating Krebs–Henseleit solution containing 11 mmol/L glucose, 100 μU/mL insulin, and 0.8 mmol/L palmitate prebound to 3% bovine serum albumin (BSA). Mechanical function of the hearts, as cardiac output × heart rate (in (mL/min)·(beats/min)·10^–2), was deteriorated in diabetic (73 ± 4) and TMZ-treated diabetic (61 ± 7) groups compared with control (119 ± 3) and TMZ-treated controls (131 ± 6). TMZ treatment increased coronary flow in TMZ-treated control (23 ± 1 mL/min) hearts compared with untreated controls (18 ± 1 mL/min). The mRNA expression of 3-ketoacyl-CoA thiolase (3-KAT) was increased in diabetic hearts. The inhibitory effect of TMZ on fatty acid oxidation was not detected at 0.8 mmol/L palmitate in the perfusate. Addition of 1 μmol/L TMZ 30 min into the perfusion did not affect fatty acid oxidation rates, cardiac work, or coronary flow. Our results suggest that higher expression of 3-KAT in diabetic rats might require increased concentrations of TMZ for the inhibitory effect on fatty acid oxidation. A detailed kinetic analysis of 3-KAT using different concentrations of fatty acid will determine the fatty acid inhibitory concentration of TMZ in diabetic state where plasma fatty acid levels are increased.