Adenosine A1 Receptor Antagonist Rolofylline Research Articles

Reversal of Tau-Dependent Cognitive Decay by Blocking Adenosine A1 Receptors: Comparison of Transgenic Mouse Models with Different Levels of Tauopathy.

The accumulation of tau is a hallmark of several neurodegenerative diseases and is associated with neuronal hypoactivity and presynaptic dysfunction. Oral administration of the adenosine A1 receptor antagonist rolofylline (KW-3902) has previously been shown to reverse spatial memory deficits and to normalize the basic synaptic transmission in a mouse line expressing full-length pro-aggregant tau (TauΔK) at low levels, with late onset of disease. However, the efficacy of treatment remained to be explored for cases of more aggressive tauopathy. Using a combination of behavioral assays, imaging with several PET-tracers, and analysis of brain tissue, we compared the curative reversal of tau pathology by blocking adenosine A1 receptors in three mouse models expressing different types and levels of tau and tau mutants. We show through positron emission tomography using the tracer [18F]CPFPX (a selective A1 receptor ligand) that intravenous injection of rolofylline effectively blocks A1 receptors in the brain. Moreover, when administered to TauΔK mice, rolofylline can reverse tau pathology and synaptic decay. The beneficial effects are also observed in a line with more aggressive tau pathology, expressing the amyloidogenic repeat domain of tau (TauRDΔK) with higher aggregation propensity. Both models develop a progressive tau pathology with missorting, phosphorylation, accumulation of tau, loss of synapses, and cognitive decline. TauRDΔK causes pronounced neurofibrillary tangle assembly concomitant with neuronal death, whereas TauΔK accumulates only to tau pretangles without overt neuronal loss. A third model tested, the rTg4510 line, has a high expression of mutant TauP301L and hence a very aggressive phenotype starting at ~3 months of age. This line failed to reverse pathology upon rolofylline treatment, consistent with a higher accumulation of tau-specific PET tracers and inflammation. In conclusion, blocking adenosine A1 receptors by rolofylline can reverse pathology if the pathological potential of tau remains below a threshold value that depends on concentration and aggregation propensity.

Targeting ASIC3 for Relieving Mice Fibromyalgia Pain: Roles of Electroacupuncture, Opioid, and Adenosine

Many scientists are seeking better therapies for treating fibromyalgia (FM) pain. We used a mouse model of FM to determine if ASIC3 and its relevant signaling pathway participated in FM pain. We demonstrated that FM-induced mechanical hyperalgesia was attenuated by electroacupuncture (EA). The decrease in fatigue-induced lower motor function in FM mice was also reversed by EA. These EA-based effects were abolished by the opioid receptor antagonist naloxone and the adenosine A1 receptor antagonist rolofylline. Administration of opioid receptor agonist endomorphin (EM) or adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) has similar results to EA. Similar results were also observed in ASIC3−/− or ASIC3 antagonist (APETx2) injected mice. Using western blotting, we determined that pPKA, pPI3K, and pERK were increased during a dual acidic injection priming period. Nociceptive receptors, such as ASIC3, Nav1.7, and Nav1.8, were upregulated in the dorsal root ganglion (DRG) and spinal cord (SC) of FM mice. Furthermore, pPKA, pPI3K, and pERK were increased in the central thalamus. These aforementioned mechanisms were completely abolished in ASIC3 knockout mice. Electrophysiological results also indicated that acid potentiated Nav currents through ASIC3 and ERK pathway. Our results highlight the crucial role of ASIC3-mediated mechanisms in the treatment of FM-induced mechanical hyperalgesia.

Adenosine A1 receptor antagonist rolofylline alleviates axonopathy caused by human Tau ΔK280

Accumulation of Tau is a characteristic hallmark of several neurodegenerative diseases but the mode of toxic action of Tau is poorly understood. Here, we show that the Tau protein is toxic due to its aggregation propensity, whereas phosphorylation and/or missorting is not sufficient to cause neuronal dysfunction. Aggregate-prone Tau accumulates, when expressed in vitro at near-endogenous levels, in axons as spindle-shaped grains. These axonal grains contain Tau that is folded in a pathological (MC-1) conformation. Proaggregant Tau induces a reduction of neuronal ATP, concomitant with loss of dendritic spines. Counterintuitively, axonal grains of Tau are not targeted for degradation and do not induce a molecular stress response. Proaggregant Tau causes neuronal and astrocytic hypoactivity and presynaptic dysfunction instead. Here, we show that the adenosine A1 receptor antagonist rolofylline (KW-3902) is alleviating the presynaptic dysfunction and restores neuronal activity as well as dendritic spine levels in vitro. Oral administration of rolofylline for 2-wk to 14-mo-old proaggregant Tau transgenic mice restores the spatial memory deficits and normalizes the basic synaptic transmission. These findings make rolofylline an interesting candidate to combat the hypometabolism and neuronal dysfunction associated with Tau-induced neurodegenerative diseases.

Risk-based evaluation of efficacy of rolofylline in patients hospitalized with acute heart failure — Post-hoc analysis of the PROTECT trial

BackgroundThe selective adenosine A1 receptor antagonist rolofylline showed a neutral overall result on clinical outcomes in the PROTECT trial. However, we hypothesized that response to rolofylline treatment could be influenced by underlying clinical risk. MethodsWe performed a post-hoc analysis of the PROTECT trial — a large, double-blind, randomized, placebo-controlled trial that enrolled 2033 patients. Baseline risk of 180-day all-cause mortality was estimated using a previously published 8-item model. Evaluation of efficacy of rolofylline across subpopulations defined based on estimated risk of mortality was performed using subpopulation treatment effect pattern plot (STEPP) analysis. Findings were validated in an independent cohort of acute heart failure patients. ResultsMedian estimated risk of mortality was 13.0%, IQR [8.0%–23.0%] and was comparable between the rolofylline and placebo arms. In low to intermediate risk subgroups of patients, rolofylline was associated with a higher rate of 180-day all-cause mortality (11.9% in the rolofylline versus 8.4% in the placebo arms, p=0.050). In the high risk subgroup of patients, particularly those with estimated risk of mortality between 20% and 30%, 180-day all-cause mortality rate was markedly lower in the rolofylline arm (18.4% in the rolofylline versus 34.0% in the placebo arms, p=0.003). The trend towards potential harm with rolofylline treatment in the low to intermediate risk subpopulations and significant benefit in high risk patients was also observed in the validation cohort. ConclusionOur findings suggest that selective adenosine A1 receptor antagonism could be harmful in low risk acute heart failure patients, while it might significantly benefit higher risk patients.

The Predictive Value of Short-Term Changes in Hemoglobin Concentration in Patients Presenting With Acute Decompensated Heart Failure

The study sought to investigate the clinical correlates and prognostic role of anemia and changes in hemoglobin in patients hospitalized for acute decompensated heart failure (AHF). Anemia is related to a poor outcome in patients with heart failure. In addition, an increase in hemoglobin during hospitalization might be a sign of effective decongestion and therefore related to improved outcome. This is a post hoc analysis of the PROTECT (Placebo-Controlled Randomized Study of the Selective Adenosine A1 Receptor Antagonist Rolofylline for Patients Hospitalized with Acute Decompensated Heart Failure and Volume Overload to Assess Treatment Effect on Congestion and Renal Function) study in 1,969 patients with AHF and mild to moderate impaired renal function. Hemoglobin levels were measured daily for the first 4 days and at day 7. The endpoint was 180-day all-cause mortality. Anemia at baseline was observed in 50.3% of the patients. During follow-up, 359 patients (18.2%) died. Hemoglobin increased in 69.1% and was associated with a better renal function at baseline and more weight loss, but was associated with a deterioration of renal function (p = 0.01), whereas total dose diuretics was lower in patients with hemoconcentration (p < 0.01). Interaction analysis showed that greater weight loss and better baseline renal function were associated with a more rapid increase in hemoglobin concentration (p < 0.01 for both). The absolute change in hemoglobin (g/dl) independently predicted outcome (hazard ratio: 0.66; 95% confidence interval: 0.51 to 0.86; p = 0.002), whereas baseline hemoglobin levels did not. Patients with AHF and preserved renal function are decongested better, as shown by an increase in hemoglobin. A rapid increase in hemoglobin during the first week is independently associated with a favorable outcome, despite a slight decrease in renal function.

Rolofylline fails to improve renal function in patients with acute HF

The adenosine A1 receptor antagonist rolofylline does not prevent persistent worsening of renal function in patients with acute heart failure and volume overload, according to the results of PROTECT, a large, phase III clinical trial. This finding is unexpected and disappointing because “initial proof-of-concept studies and a 301-patient pilot study suggested that selective adenosine A1 receptor antagonists could enhance diuresis while preserving or improving renal function in this high-risk population,” reports Dr Michael Givertz, one of the trial investigators.

Effects of the Adenosine A1 Receptor Antagonist Rolofylline on Renal Function in Patients With Acute Heart Failure and Renal Dysfunction: Results From PROTECT (Placebo-Controlled Randomized Study of the Selective A1 Adenosine Receptor Antagonist Rolofylline for Patients Hospitalized With Acute Decompensated Heart Failure and Volume Overload to Assess Treatment Effect on Congestion and Renal Function)

This study sought to assess the effects of rolofylline on renal function in patients with acute heart failure (AHF) and renal dysfunction randomized in PROTECT (Placebo-Controlled Randomized Study of the Selective A1 Adenosine Receptor Antagonist Rolofylline for Patients Hospitalized With Acute Decompensated Heart Failure and Volume Overload to Assess Treatment Effect on Congestion and Renal Function). Small studies have indicated that adenosine A1 receptor antagonists enhance diuresis and may improve renal function in patients with chronic heart failure or AHF. A total of 2,033 patients with AHF, volume overload, estimated creatinine clearance between 20 and 80 ml/min, and elevated natriuretic peptide levels were randomized (2:1) within 24 h of hospital presentation to rolofylline 30 mg/day or intravenous placebo for up to 3 days. Creatinine was measured daily until discharge or day 7 and on day 14. Persistent worsening renal function was defined as an increase in serum creatinine ≥0.3 mg/dl at both days 7 and 14, or initiation of hemofiltration or dialysis or death by day 7. At baseline, mean ± SD estimated creatinine clearance was 51.0 ± 20.5 ml/min in the placebo group and 50.4 ± 20.0 ml/min in the rolofylline group. Changes in creatinine and estimated creatinine clearance were similar between placebo- and rolofylline-treated patients during hospitalization and at day 14. After 4 days, mean body weight was reduced by 2.6 and 3.0 kg in placebo and rolofylline patients, respectively (p = 0.005). Persistent worsening renal function occurred in 13.7% of the placebo group and 15.0% of the rolofylline group (odds ratio vs. placebo: 1.11 [95% confidence interval: 0.85 to 1.46]; p = 0.44). In this large, phase III clinical trial, the adenosine A1 receptor antagonist rolofylline did not prevent persistent worsening renal function in AHF patients with volume overload and renal dysfunction. (A Study of the Selective A1 Adenosine Receptor Antagonist KW-3902 for Patients Hospitalized With Acute HF and Volume Overload to Assess Treatment Effect on Congestion and Renal Function [PROTECT-1], NCT00328692; and [PROTECT-2], NCT00354458)

Early dyspnoea relief in acute heart failure: prevalence, association with mortality, and effect of rolofylline in the PROTECT Study

Dyspnoea and pulmonary and/or peripheral congestion are the most frequent manifestations of acute heart failure (AHF) and are important targets for therapy. We have assessed changes in dyspnoea, their relationship with mortality, and the effects of the adenosine A1 receptor antagonist rolofylline on these endpoints in patients enrolled in the PROTECT trial. PROTECT was a prospective, double-blind, placebo-controlled study assessing the effect of rolofylline in patients hospitalized for AHF with dyspnoea, fluid overload, increased plasma natriuretic peptides, and mild-to-moderate renal dysfunction. Early dyspnoea relief, prospectively defined as moderately or markedly better dyspnoea at both 24 and 48 h after the start of study drug administration, occurred in 49.8% of the patients. Early dyspnoea relief was associated with greater weight loss and with reduced mortality at Days 14 and 30 [hazard ratio (HR) 0.28, 95% confidence interval (CI): 0.15, 0.50; and 0.35, 95% CI: 0.22, 0.55, respectively]. Rolofylline administration was associated with an increase in the proportion of patients showing early dyspnoea relief (HR 1.30; 95% CI: 1.08, 1.57) and with a numerically lower mortality at 14 and 30 days, largely driven by the mortality due to HF [at 30 days, HR (95% CI, P-value): 0.65 (0.38-1.10, P= 0.107)]. Rolofylline did not reduce episodes of in-hospital worsening HF or post-discharge re-admissions, nor did it improve survival at 60 or 180 days. The present analysis from PROTECT demonstrated that more weight loss was associated with early dyspnoea relief and reduced short-term mortality.