Improvement of cerebral blood flow by olprinone, a phosphodiesterase-3 inhibitor, in mild heart failure

Electro-organic synthesis of tetrahydroimidazo[1,2-a]pyridin-5(1H)-one via a multicomponent reaction

Electro-synthesis through a one-pot three-component condensation of corresponding aldehydes, Meldrum's acid, and 2-(nitromethylene)imidazolidine resulted in a series of novel tetrahydroimidazo[1,2-a]pyridine-5(1H)-one derivatives containing an electronegative pharmacophore (=CNO₂). The process was carried out in propanol medium with sodium bromide presented as electrolyte, inside an undivided cell with good to excellent yields. As a powerful entry into fused polycyclic structures related to bioactive heterocycles, this green protocol shows great potential.

Hippocampal Blood Flow Abnormality Associated With Depressive Symptoms and Cognitive Impairment in Patients With Chronic Heart Failure

BACKGROUND

Depressive symptoms and memory impairment are prevalent in patients with chronic heart failure (CHF). Although the mechanisms remain to be elucidated, the hippocampus (an important brain area for emotion and memory) may be a possible neural substrate for these symptoms.

METHODS AND RESULTS

We prospectively enrolled 40 Stage C patients, who had past or current CHF symptoms, and as controls 40 Stage B patients, who had structural heart disease but had never had CHF symptoms, in Brain Assessment and Investigation in Heart Failure Trial (B-HeFT) (UMIN000008584). As the primary index, we measured cerebral blood flow (CBF) in the 4 anterior-posterior segments of the hippocampus, using brain MRI analysis. Depressive symptoms, immediate memory (IM) and delayed memory (DM) were assessed using Geriatric Depression Scale (GDS), and Wechsler Memory Scale-revised (WMS-R), respectively. Hippocampus CBF in the most posterior segment was significantly lower in Stage C than in Stage B group (P=0.029 adjusted for Holm's method). Multiple regression analysis identified significant association between hippocampus CBF and GDS or DM score in Stage C group (all P<0.05). GDS score was significantly higher, and IM and DM scores were lower in Stage C patients with hippocampus CBF below the median than those with hippocampus CBF above the median (all P<0.05).

CONCLUSIONS

Hippocampus abnormalities are associated with depressive symptoms and cognitive impairment in CHF patients. (Circ J 2016; 80: 1773-1780).

Sulfonic acid functionalized silica-coated CuFe2O4 core–shell nanoparticles: an efficient and magnetically separable heterogeneous catalyst for the synthesis of 2-pyrazole-3-amino-imidazo-fused polyheterocycles

Synthesis of easily separable magnetic core–shell nanoparticles and their efficient use as catalyst in a multicomponent reaction.

Heart and brain interconnection - clinical implications of changes in brain function during heart failure

Heart failure (HF) is a highly prevalent disorder worldwide and, consequently, a burden on the healthcare systems of many nations. Although the effects of HF are systemic, many therapeutic targets are focused on cardiac dysfunction. The brain is closely related to the heart, but there are few reports on the relationship between these organs. We describe the effects of the brain on HF progression. Specific brain regions control sympathetic drive and neurohumoral factors, which play an important role in disease exacerbation. In addition, we review some of our previous studies on deranged cerebral metabolism and reduced cerebral blood flow during HF. Although the reasons underlying these effects during HF remain uncertain, we propose plausible mechanisms for these phenomena. In addition, the clinical implications of such conditions in terms of predicting prognosis are discussed. Finally, we investigate cognitive impairment in patients with HF. Cognitive impairment through cerebral infarction or hypoperfusion is associated with adverse outcomes, including death. This brief review of brain function during the development of HF should assist with future strategies to better manage patients with this condition.

I2–DMSO–PTSA: a simple and metal free oxidative cross coupling of imidazo[1,2-a]pyridines and methylketones

A simple, metal free and selective oxidative cross-coupling promoted by I₂–DMSO in presence of PTSA has been developed with the use of imidazo[1,2-a]pyridines (1) and methyl ketones (2) to access 3 in a one pot reaction.

Sulfamic acid-functionalized hydroxyapatite-encapsulated γ-Fe2O3 nanoparticles as a magnetically recoverable catalyst for synthesis of N-fused imidazole-quinoline conjugates under solvent-free conditions

γ-Fe₂O₃-HAp-(CH₂)₃-NHSO₃H was shown to be a powerful and reusable catalyst for the synthesis of N-fused imidazole-quinoline conjugates under solvent-free conditions.

Iodine–triphenylphosphine mediated sulfenylation of imidazoheterocycles with sodium sulfinates

An efficient approach to sulfenyl imidazoheterocycles has been developed via iodine–triphenylphosphine mediated direct sulfenylation of imidazoheterocycles with sodium sulfinates under transition-metal-free conditions.

Multicomponent solvent-free synthesis of benzimidazolyl imidazo[1,2-a]-pyridine under microwave irradiation

A novel one-pot, three-component reaction employing variously substituted benzimidazole-linked amino pyridines, aldehydes, and isonitriles catalyzed by scandium(III) triflate under solvent-free conditions were accomplished. This new synthetic methodology facilitates the rapid generation of intricate molecular frameworks in three-dimensional fashion leading to benzimidazole-imidazo[1,2-a] pyridines. This approach is envisioned as an environmentally benign process and a simple operation to the biological interesting compounds. The present synthetic sequence permits the introduction of three points of structural diversity to expand chemical space with high purity and excellent yields.

Cerebral blood flow as a marker for recovery of left ventricular systolic dysfunction in patients with idiopathic dilated cardiomyopathy

BACKGROUND

This study was intended to investigate whether cerebral blood flow (CBF) could predict the recovery of left ventricular (LV) systolic dysfunction in patients with idiopathic dilated cardiomyopathy (DCMP).

METHODS AND RESULTS

Between July 2001 and March 2009, 107 patients who had been diagnosed with idiopathic DCMP underwent radionuclide angiography to assess their CBF. The recovery of LV systolic dysfunction was defined as recovery of the ejection fraction (EF) measured by transthoracic echocardiography to a level of 40% or greater and an increase of 10% or greater in its absolute value during follow-up. The EF was followed for at least 36 months if it did not recover. Thirty-four patients (31.8%) recovered and had greater CBF than the nonrecovered patients (41.9 ± 3.4 vs. 37.1 ± 4.9 mL/min/100g, P < .001). On multivariate logistic analysis, CBF (odds ratio 1.216) and symptom duration (odds ratio 0.952) were independent predictors of the recovery of LV systolic dysfunction. There was also a weak negative correlation between CBF and symptom duration (r = -0.334, P < .001). Furthermore, CBF was associated with LVEF improvement seen at the 1- and 2-year follow-up times according to multiple linear regression analysis.

CONCLUSIONS

CBF was associated with recovery of LV systolic dysfunction in patients with idiopathic DCMP. Therefore, measurement of CBF would be helpful to predict the clinical course of their disease.

Imidazo[1,2-a]pyridines susceptible to excited state intramolecular proton transfer: one-pot synthesis via an Ortoleva-King reaction

A short and efficient route to a broad range of imidazo[1,2-a]pyridines from 2-aminopyridines and acetophenones is achieved by a tandem, one-pot process starting with an Ortoleva-King reaction. Optimal conditions for the first step were established after examining various reaction parameters (solvent, reagent ratios, and temperature). The conditions identified (1st step, neat, 2.3 equiv of 2-aminopyridine, 1.20 equiv of I(2), 4 h, 110 °C; 2nd step, NaOH(aq), 1 h, 100 °C) resulted in the formation of imidazo[1,2-a]pyridines in 40-60% yields. The synthesis is compatible with various functionalities (OH, NMe(2), Br, OMe). Products containing a 2-(2'-hydroxyphenyl) substituent undergo excited state intramolecular proton transfer (ESIPT) in nonpolar and polar-aprotic solvents. Although ESIPT-type emission in nonpolar solvents is weak, the Stokes shifts are very high (11000 cm(-1)). The comparison of the properties of six ESIPT-capable imidazo[1,2-a]pyridines shows the influence of various substituents on emission characteristics. All of them also display strong, solid-state emission in blue-green-yellow region. 2-Aryl-imidazo[1,2-a]pyridines not capable of ESIPT emit in the blue region, displaying high fluorescence quantum yield.

Association of cerebral blood flow with the development of cardiac death or urgent heart transplantation in patients with systolic heart failure

AIMS

Although cerebral blood flow (CBF) is known to be low in patients with advanced systolic heart failure (HF), little is known of the prognostic significance of this observation. We investigated whether CBF might be associated with the development of adverse outcomes in systolic HF, and whether it might provide prognostic information in addition to that provided by exercise tests.

METHODS AND RESULTS

We performed a prospective observational study involving 224 systolic HF patients (left ventricular ejection fraction ≤35%). The study endpoint was the occurrence of cardiac death or urgent heart transplantation. Global CBF was measured using radionuclide angiography. Clinical, biochemical, echocardiographic, and exercise data were also obtained. During follow-up (median 36 months), 52 patients experienced death or urgent transplantation. Multivariable analysis showed that global CBF, the minute ventilation/carbon dioxide production (VE/VCO(2)) slope, New York Heart Association functional class ≥III, symptom duration ≥12 months, serum sodium, and serum creatinine were associated with the development of the endpoint. Patients with a CBF <35.4 mL/min/100 g were at increased risk of death or urgent transplantation (hazard ratio = 2.47; 95% confidence interval, 1.35-4.52). The addition of global CBF to a prognostic model including the VE/VCO(2) slope increased the C-index for the prediction of adverse outcomes with borderline significance.

CONCLUSION

Cerebral blood flow was associated with the development of long-term outcomes in systolic HF, and therefore may be useful in identifying patients suitable for heart transplantation. This finding is especially relevant for patients in whom exercise tests may not be performed sufficiently.

The effects of the phosphodiesterase inhibitor olprinone on global cerebral ischemia

BACKGROUND

The phosphodiesterase III inhibitor olprinone has been confirmed to improve myocardial function and increase cerebral blood flow; therefore, if olprinone exerts direct neuroprotective effects against global cerebral ischemia to the same degree as cilostazol, olprinone could be useful for cerebral resuscitation after cardiac arrest. We examined whether olprinone directly protected neuronal cells from global cerebral ischemia both in vivo and in vitro.

METHODS

In a rat model of 10-minute global cerebral ischemia induced by 4-vessel occlusion, 0.3, 3, or 30 microg x kg(-1) x min(-1) olprinone or saline was infused for a periischemic period of 40 minutes (n = 6 for each group). Hippocampal CA1 neuronal cells were then counted 3 days after reperfusion, and the phosphorylation of cyclic adenosine 3'5'-monophosphate response element-binding protein was examined using Western blotting analyses of specimens obtained 15 minutes after reperfusion. In vitro, cultured cerebral neurons were exposed to 4 hours of hypoxia and glucose deprivation and then 24 hours of recovery in the absence or presence of olprinone (10(-11)-10(-5) mol x L(-1)). Cell viability was measured using the Cell Counting Kit-8 (Dojindo Molecular Technologies, Gaithersburg, MD).

RESULTS

In the rat model of global ischemia, the number of surviving CA1 neurons counted under a microscopic field in the 30 microg x kg(-1) x min(-1) olprinone-treated group (49.9 +/- 9.2) was significantly higher than that in the saline infusion control group (7.2 +/- 3.4), and olprinone treatment increased the phosphorylation of cyclic adenosine 3'5'-monophosphate response element-binding protein. The survival fraction of the neuronal cells cultured in the presence of olprinone was also significantly higher than that of cells cultured in the absence of olprinone in a dose-dependent manner.

CONCLUSIONS

Our study successfully demonstrated, for the first time, that olprinone had a protective effect on neuronal cells in vitro and in vivo, especially against global cerebral ischemia. These results suggest that olprinone might be useful for the treatment of patients experiencing global cerebral ischemia.

The phosphodiesterase III inhibitor olprinone inhibits hippocampal glutamate release via a cGMP/PKG pathway

Olprinone, an inhibitor of cyclic nucleotide phosphodiesterase III, inhibited an increase in intracellular Ca(2+) concentrations for acutely dissociated rat hippocampal pyramidal neurons induced by extracellular high K(+) (35 mM) depolarization. Olprinone (100 microM) significantly reduced spontaneous glutamate release from rat hippocampal slices. Furthermore, olprinone significantly decreased the rate of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated miniature excitatory postsynaptic currents (AMPA-mEPSCs) monitored from CA1 pyramidal neurons of rat hippocampal slices, and the effect was blocked by KT5823, an inhibitor of protein kinase G (PKG), but not by H-89, an inhibitor of protein kinase A (PKA). In the PKA assay using PC-12 cells, olprinone did not activate PKA. Taken together, the results of the present study show that olprinone attenuates intracellular Ca(2+) rise through voltage-sensitive Ca(2+) channels and inhibits presynaptic glutamate release via a cGMP/PKG pathway.

Efficient solid-phase synthesis of a library of imidazo[1,2-a]pyridine-8-carboxamides

A versatile method for the solid-phase synthesis of imidazo[1,2-a]pyridine-based derivatives, imidazo[1,2-a]pyridine-8-carboxamides, has been developed. They were obtained by treatment of the amino group of the polymer-bound 2-aminonicotinate with different alpha-haloketones, followed by halogenation at the 3-position of the polymer-bound imidazo[1,2-a]pyridine. The derived polymer-bound imidazo[1,2-a]pyridines 5, 6, and 7 were finally cleaved from the solid-support with an excess of primary or secondary amines. The final crude products were purified from excess amines by solid-supported liquid-liquid extraction (SLE).

8-Fluoroimidazo[1,2-a]pyridine: synthesis, physicochemical properties and evaluation as a bioisosteric replacement for imidazo[1,2-a]pyrimidine in an allosteric modulator ligand of the GABA A receptor

8-Fluoroimidazo[1,2-a]pyridine has been established as a physicochemical mimic of imidazo[1,2-a]pyrimidine, using both in silico and traditional techniques. Furthermore, a novel synthesis of a 3,7-disubstituted-8-fluoroimidazopyridine 3 has been developed and the utility of the physicochemical mimicry has been demonstrated in an in vitro system. Here, the 8-fluoroimidazopyridine ring contained in ligand 3 acts as a bioisosteric replacement for imidazopyrimidine in the GABA(A) receptor modulator 2.