Piero Pollesello

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Positive inotropic responses upon administration of milrinone, an inhibitor of the phosphodiesterase enzyme (PDE), involve a well-pronounced positive chronotropic effect. Here we tested whether milrinone evokes this chronotropic response solely by PDE inhibition or by a concerted action that involve additional pharmacological targets. Milrinone stimulated increases in heart rate were studied in right atrial preparations of guinea pig in the presence or absence of inhibitors of putative ancillary molecular pathways or ion channels: i.e. β receptor blockers with distinct selectivities (propranolol, metoprolol, and carvedilol), α1 receptor blocker (prazosin), inhibitor of the small conductance Ca²⁺ activated K⁺ (SK) channels (apamin), L-type Ca²⁺ channel blockers (verapamil and diltiazem), and different Na⁺ channel blockers (lidocaine, tetrodotoxin, and quinidine). Carvedilol, which inhibits β1, β2, α1 and 5-HT receptors, limited the positive chronotropic effects of milrinone to about 40%, (p2+ channels, only non-significant trends towards reductions of the milrinone effects were seen. The α1 receptor blocker prazosin did not limit the milrinone evoked positive chronotropy. Blockers of Na⁺ channels, SK channels, or the β1 receptor blocker, metoprolol also did not affect the positive chronotropy evoked by milrinone. We conclude that milrinone increases heart rate in response to adrenergic signaling, that besides PDE inhibition, may involve a 5-HT-receptor-dependent component. Our exploratory approach paves the way to more focused experiments with the use of selective 5-HT-receptor antagonists to confirm or reject the involvement of a specific 5-HT-receptor dependent pathway.

The effects of the calcium sensitizer levosimendan on hemodynamics and survival in guinea pigs intoxicated with the calcium blockers verapamil or diltiazem were evaluated in a randomized controlled study. One hundred four animals were randomized to be intoxicated with either verapamil (2.0 mg/kg) or diltiazem (4.5 mg/kg) and thereafter further randomized into 6 groups which received either saline (control), 3 different regimes of levosimendan, calcium chloride, and levosimendan combined with calcium chloride. The hemodynamics and survival of the animals were followed for 60 minutes after intoxication. The negative inotropic effect of calcium blockers was seen as a decrease by over 70% of the positive derivative of the left ventricular pressure. This was reversed by levosimendan. Moreover, both verapamil and diltiazem-induced marked hypotension (−69% and −63% of the baseline value, respectively) which was also reversed by levosimendan. The combined levosimendan and calcium chloride treatment had a synergistic effect in reversing verapamil or diltiazem-induced deterioration in hemodynamics. Both verapamil and diltiazem intoxications decreased the survival rate of guinea pigs to 13%. Levosimendan addition improved survival dose-dependently up to a survival rate of 75% and 88% in the verapamil and diltiazem groups, respectively. Low dose of levosimendan combined with calcium chloride improved survival in verapamil and diltiazem group to 88% and 100%, respectively. In conclusion, the administration of levosimendan improved hemodynamics and survival in calcium channel blocker intoxicated guinea pigs. The synergistic effect of levosimendan and calcium chloride suggests that this combination could be an effective antidote in calcium channel blocker intoxications.

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In the 1980s, Orion Pharma, then a mid-ranking Nordic area pharmaceutical company, established a drug development programme on the inhibition of catechol O-methyltransferase (COMT). This enzyme, which plays an important role in the inactivation of catecholamine neurotransmitters and drugs with a catechol structure, thus came under consideration as a target in the innovative translational and clinical programme we describe in this historical review. The starting point was the conjecture that a peripherally acting COMT inhibitor might improve entry of levodopa into the brain. This had potentially significant implications for the medical treatment of Parkinson’s disease (PD). The rationale was that more efficient delivery of levodopa to the brain might allow the high therapeutic doses of levodopa to be reduced and the dose interval to be extended. Elucidation of structure–activity relations paved the way for the discovery and development of entacapone, a 5-nitrocatechol that was a potent and highly specific inhibitor of COMT. Experience in phase III clinical trials established that entacapone, used as an adjunct to regular or controlled-release levodopa preparations (also including a peripherally acting dopa-decarboxylase inhibitor), increased ON-time and reduced OFF-time and improved clinical condition in patients with PD experiencing wearing-off, often with a reduced daily levodopa dose. Several of these studies also identified that entacapone improved patients’ quality of life and was cost-effective. Subsequently, entacapone has been amalgamated into a triple-combination preparation (Stalevo®) with levodopa and carbidopa to create a flexible and convenient drug therapy for patients with PD who have end-of-dose motor fluctuations not stabilised on levodopa/dopa-decarboxylase inhibitor treatment. This review offers a historical perspective on a successful programme of drug development by researchers who played central roles in the progress from exploratory hypothesis to registered pharmaceutical product.

In the latest years, several studies described the impact of repetitive/intermittent i.v. levosimendan treatment in the management of advanced heart failure. For this updated review, we systematically searched the literature for clinical trials, registries, and real-world data and identified 31 studies that we commented in a narrative review: 3814 patients were described, of whom 1744 were treated repetitively with levosimendan. On the basis of the nature of the study protocols and of the end points, out of those studies, we further selected 9 that had characteristics, making them suitable for a meta-analysis on mortality. This short list describes data from 680 patients (of whom 399 received repeated doses of levosimendan) and 110 death events (of which 50 occurred in the levosimendan cohort). In the meta-analysis, repetitive/intermittent therapy with i.v. levosimendan was associated with a significant reduction in mortality at the longest time point available: 50 of 399 (12.5%) versus 60 of 281 (21.4%) in the control arms, with a risk ratio of 0.62 (95% confidence interval, 0.42–0.90; P < 0.01). In a sensitivity analysis, removing each trial and reanalyzing the remaining data set did not change the trend, magnitude, or significance of the results. A visual inspection of the funnel plot did not suggest publication bias. The results provide a very strong rationale for continuing to investigate the repetitive use of levosimendan in patients with advanced heart failure by properly powered regulatory clinical trials. Meanwhile, it seems that the use of repetitive/intermittent i.v. levosimendan infusions has become one of the few effective options for preserving the hemodynamic and symptomatic balance in such patients.

The art of narrative and storytelling in scientific prose is now considered as an integral part of any well-rounded scientific communication process. Hence, when the AI-driven ChatGPT facility was made available online many scientists wanted to assess this new marvel. Over the course of several months, we explored its functionalities and opportunities in the field of scientific publication and collected both positive and negative experiences.Among the latter, the most compelling example was asking ChatGPT for scientific references. In this short communication we describe dialogs in which we sought to steer the AI towards fact-based assertions while it continued to produce false citations of papers, abstracts, communication to non-existing congresses, etc.Through exchanges on the forum of the open AI platform we realized that other scientists have encountered the same problem, even when searching for patents and industrial property rights.Our recommendation is that the AI of ChatGPT would be instructed on the role and uniqueness of scientific paper citations. Moreover, relevant agencies should plan for creating and adopting policies to rule out inappropriate behaviors by AI in fields in which errors could cost (at least) loss of trust in science by the general population.

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Levosimendan is an inodilator drug that, given its unique pharmacological actions and safety profile, represents a viable therapeutic option in patients with heart failure with reduced ejection fraction in the advanced stage of the disease (advHFrEF). Pulsed levosimendan infusion in patients with advHFrEF improves symptoms and clinical and hemodynamic status, prevents recurrent hospitalizations, and enables optimization of guidelines-directed medical therapy. Furthermore, considering its proprieties on right ventricular function and pulmonary circulation, levosimendan could be helpful for the prevention and treatment of the right ventricular dysfunction post-implanting a left ventricular assist device. However, to date, evidence on this issue is scarce and has yielded mixed results. Finally, preliminary experiences indicate that treatment with levosimendan at scheduled intervals may serve as a “bridge to transplant” strategy in patients with advHFrEF. In this review, we summarized the clinical pharmacology of levosimendan, the available evidence in the treatment of patients with advHFrEF, as well as a hypothesis for its use in patients with advanced heart failure with preserved ejection fraction.