Cardiac toxicity of the echinocandins: chance or cause and effect association?

Caspofungin-Induced Cardiotoxicity in Patients Treating for Candidemia

Echinocandins selectively inhibit fungal cell wall synthesis and, therefore, have few side effects. However, there are reports of hemodynamic and cardiac complications. We conducted this study to investigate the effects of caspofungin both on the noninvasive echocardiographic indices of myocardial function and myocardial injury based on serum high-sensitivity cardiac troponin I (hs-cTnI) levels. This study was conducted on patients treated for candidemia. The hs-cTnI level and echocardiographic parameters were measured before and 1 h after the infusion of the induction dose of caspofungin. Data were compared between central and peripheral venous drug administration routes. Fifteen patients were enrolled in the study. There were no significant differences in the echocardiographic parameters between the baseline and post-treatment period. The mean hs-cTnI level exhibited a significant rise following drug administration (0.24 ± 0.2 ng/mL vs 0.32 ± 0.3 ng/mL; p = 0.006). There was also a significant difference concerning the hs-cTnI level between central and peripheral venous drug administration routes (p = 0.034). Due to differences in the hs-cTnI level, it appears that the administration of caspofungin may be associated with myocardial injury. Our findings also showed a higher possibility of cardiotoxicity via the central venous administration route.

Potent antifungal agents and use of nanocarriers to improve delivery to the infected site: A systematic review

There are four major classes of antifungals with the predominant mechanism of action being targeting of cell wall or cell membrane. As in other drugs, low solubility of these compounds has led to low bioavailability in target tissues. Enhanced drug dosages have effects such as toxicity, drug-drug interactions, and increased drug resistance by fungi. This article reviews the current state-of-the-art of antifungals, structure, mechanism of action, other usages, and toxic side effects. The emergence of nanoformulations to transport and uniformly release cargo at the target site is a boon in antifungal treatment. The article details research that lead to the development of nanoformulations of antifungals and potential advantages and avoidance of the lacunae characterizing conventional drugs. A range of nanoformulations based on liposomes, polymers are in various stages of research and their potential advantages have been brought out. It could be observed that under similar dosages, test models, and duration, nanoformulations provided enhanced activity, reduced toxicity, higher uptake and higher immunostimulatory effects. In most instances, the mechanism of antifungal activity of nanoformulations was similar to that of regular antifungal. There are possibilities of coupling multiple antifungals on the same nano-platform. Increased activity coupled with multiple mechanisms of action presents for nanoformulations a tremendous opportunity to overcome antifungal resistance. In the years to come, robust methods for the preparation of nanoformulations taking into account the repeatability and reproducibility in action, furthering the studies on nanoformulation toxicity and studies of human models are required before extensive use of nanoformulations as a prescribed drug.

Biofilms and beyond: expanding echinocandin utility

Echinocandins have been in use for over 15 years, starting with the first approval in 2001. Current trends, such as increasing resistance to fluconazole and shifts toward non-albicans spp. of Candida, suggest a growing role for echinocandins, as reflected by recent (2016) updates to guidelines that recommend echinocandins as first-line treatment for candidaemia. The efficacy, tolerability, and safety of echinocandins and their target site of action (1,3-β-d-glucan synthesis) have prompted research into potential new uses, such as for treatment of biofilm infections, MDR Candida auris and dermatophytes. Moreover, new mycobiome discoveries linking inflammatory bowel disease (IBD; for instance Crohn's disease) to fungi have led to preliminary but encouraging data regarding echinocandin therapy and treatment of IBD. In this article, we will review the available evidence and potential utility of echinocandins and 1,3-β-d-glucan synthesis inhibition in these areas of emerging interest.

Caspofungin Modulates Ryanodine Receptor-Mediated Calcium Release in Human Cardiac Myocytes

Recent studies showed that critically ill patients might be at risk for hemodynamic impairment during caspofungin (CAS) therapy. The aim of our present study was to examine the mechanisms behind CAS-induced cardiac alterations. We revealed a dose-dependent increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) after CAS treatment. Ca²⁺ ions were found to be released from intracellular caffeine-sensitive stores, most probably via the activation of ryanodine receptors.

Safety and Efficacy of Intermittent Intravenous Administration of High-Dose Micafungin

BACKGROUND

The use of mold-active azoles for antifungal prophylaxis after allogeneic stem cell transplantation (SCT) is hindered by adverse events and drug-drug interactions. Higher doses of echinocandins administered intermittently may be an alternative in this setting.

METHODS

This was a single-center, observational 5-year study to characterize the safety and efficacy of intermittent administration of high-dose intravenous micafungin (≥5 doses of ≥300 mg micafungin 2-3 times weekly) in patients with acute leukemia and allogeneic SCT recipients.

RESULTS

A total of 104 patients (84 allogeneic SCT recipients and 20 patients with leukemia) received intermittent high-dose intravenous micafungin, 83 (79.8%) as prophylaxis. Large variability in the micafungin dosing regimen was observed; 78 (75%) patients received >75% of their course as 300 mg micafungin 3 times weekly. Liver function tests decreased from baseline to end of treatment (EOT; P < .001). Patients with normal baseline liver function (n = 55 [52%]) maintained similar enzyme levels throughout the study. For patients with abnormal baseline liver function (n = 49 [47%]), liver function tests significantly improved from baseline to EOT (P ≤ .005). Duration and/or micafungin dosing algorithms were not associated with liver toxicity at EOT. There were no significant changes in renal function, and infusion-related reactions or deaths were not observed. Five of 83 (6.0%) patients in the prophylaxis group developed a breakthrough fungal infection.

CONCLUSIONS

In this largest cohort of patients to date, intermittent administration of high-dose micafungin was well tolerated, without any associated liver or renal function abnormalities, and may be considered an alternative antifungal prophylactic strategy. Prospective studies are needed to further validate these findings.

Development of New Strategies for Echinocandins: Progress in Translational Research

Echinocandins are N-acyl-substituted cyclic hexapeptides with potent in vitro and in vivo activity against Candida species that are used for primary treatment and prevention of candidemia and invasive candidiasis. Recent progress in the translational research of echinocandins has led to new approaches for treatment of central venous catheter Candida biofilms. Other studies have laid the experimental and clinical foundation for use of extended dosing intervals for administration of echinocandins in treatment and prevention of candidemia and invasive candidiasis.

[Echinocandins: Applied pharmacology]

The echinocandins share pharmacodynamic properties, although there are some interesting differences in their pharmacokinetic behaviour in the clinical practice. They are not absorbed by the oral route. They have a somewhat special distribution in the organism, as some of them can reach high intracellular concentrations while, with some others, the concentration is reduced. They are highly bound to plasma proteins, thus it is recommended to administer a loading dose for anidulafungin and caspofungin, although this procedure is not yet clear with micafungin. Echinocandins are excreted via a non-microsomal metabolism, so the urinary concentration is very low. Some carrier proteins that take part in the biliary clearance process are probably involved in the interactions described with caspofungin and micafungin. These two drugs must be used with caution in patients with severely impaired hepatic function, while all of them can be used without special precautions when there is renal impairment or the patient requires renal replacement therapy.

Cardiac Effects of Echinocandins in Endotoxemic Rats

Echinocandins are known as effective and safe agents for the prophylaxis and treatment of different cohorts of patients with fungal infections. Recent studies revealed that certain pharmacokinetics of echinocandin antifungals might impact clinical efficacy and safety in special patient populations. The aim of our study was to evaluate echinocandin-induced aggravation of cardiac impairment in septic shock. Using an in vivo endotoxemic shock model in rats, we assessed hemodynamic parameters and time to hemodynamic failure (THF) after additional central-venous application of anidulafungin (2.5 mg/kg of body weight [BW]), caspofungin (0.875 mg/kg BW), micafungin (3 mg/kg BW), and control (0.9% sodium chloride). In addition, echinocandin-induced cytotoxicity was evaluated in isolated rat cardiac myocytes. THF of the animals in the caspofungin group (n = 7) was significantly reduced compared to that in the control (n = 6) (136 min versus 180 min; P = 0.0209). The anidulafungin group (n = 7) also showed a trend of reduced THF (136 min versus 180 min; log-rank test P = 0.0578). Animals in the micafungin group (n = 7) did not show significant differences in THF compared to those in the control. Control group animals and also micafungin group animals did not show altered cardiac output (CO) during our experiments. In contrast, administration of anidulafungin or caspofungin induced a decrease in CO. We also revealed a dose-dependent increase of cytotoxicity in anidulafungin- and caspofungin-treated cardiac myocytes. Treatment with micafungin did not cause significantly increased cytotoxicity. Further studies are needed to explore the underlying mechanism.

Influence of echinocandin administration on hemodynamic parameters in medical intensive care unit patients: a single center prospective study

PURPOSE

Fungal infections present a constant risk to critically ill and immunocompromised patients. Therefore, treatment guidelines recommend echinocandins as first-line antifungals in critically ill patients to improve patient outcomes. Echinocandins are usually well tolerated; nevertheless, rare adverse events can occur. There are reports of temporary deterioration of hemodynamic parameters during loading doses, especially in critically ill patients. The objective of this study is to analyze the hemodynamic changes during administration of the echinocandin antifungals, caspofungin and anidulafungin, in medical intensive care unit patients.

METHODS

A prospective study in medical ICU patients receiving echinocandins was monitored using single-indicator transpulmonary thermodilution (TPTD). TPTD measurements were performed immediately before, directly after, and 4 h after echinocandins on two following days.

RESULTS

Mean arterial pressure and also diastolic blood pressure showed significant changes (p < 0.042 and p < 0.007) after echinocandin application in the measurement immediately after application, but not after 4 h. Basic hemodynamic parameters as well as the TPTD-derived cardiac function parameters did not significantly change after echinocandin application at all. In patients with the need for norepinephrine therapy, the vasopressor dose was not statistically significantly altered.

CONCLUSION

To conclude, administration of echinocandins in this observed study population is safe, even in severely critically ill patients if application rules of these agents are followed. However, adverse effects could be observed and practitioners should be cognizant of these effects. These observations can be optimized by high-level assessments, such as the pulse contour cardiac output monitoring, and clinicians should continue to be vigilant with cardiac monitoring of patients receiving echinocandin antifungals.

Cardiac response to centrally administered echinocandin antifungals

OBJECTIVES

The purpose of this study was to determine the effect of the echinocandin antifungals on the cardiac system, including cardiac output, blood pressure and heart rate, when administered in an in-vivo model.

METHODS

The echinocandin antifungals were administered via central line to male Sprague-Dawley rats. Cardiac imaging and functional measurements were made using a high-resolution in-vivo imaging system. Statistical comparisons of the experimental antifungals versus saline control were made using a Student's t-test.

KEY FINDINGS

In cardiac output (CO) measurements, caspofungin was associated with a bimodal distribution in results at 3 mg/kg. Those with little response, termed 'non-vulnerable' animals (n = 3) had no significant change in CO from baseline (-4.6 ± 10.7%). Other animals, termed 'vulnerable' animals (n = 3 at 3 mg/kg and those dosed at 6 mg/kg (n = 6)), experienced greater than 60% decrease in CO (-66.4 ± 13.1% at 3 mg/kg and -62.9 ± 13.0% at 6 mg/kg, P < 0.05). A dose of 5 mg/kg anidulafungin was associated with no significant changes in CO (-16.1 ± 26%), while 11.5 mg/kg decreased CO by 62.7 ± 19.4% from baseline (P < 0.05). With micafungin 1 mg/kg and 5 mg/kg doses, changes in CO were not significant (-16.7 ± 2.1% and -18.2 ± 1.9%, respectively).

CONCLUSIONS

These studies provide substantial evidence to support ex-vivo Langendorff and in-vitro mitochondrial studies demonstrating a similar pharmacological event. Clinical reports of similar effects also support these findings.

Predicting mitochondrial targeting by small molecule xenobiotics within living cells using QSAR models

Whether small molecule xenobiotics (biocides, drugs, probes, toxins) will target mitochondria in living cells can be predicted using an algorithm derived from QSAR modeling. Application of the algorithm requires the chemical structures of all ionic species of the xenobiotic compound in question to be defined, and for certain numerical structure parameters (AI, CBN, log P, pKa, and Z) to be obtained for all such species. How the chemical structures are specified, how the structure parameters are obtained or estimated, and how the algorithm is used are described in an explicit protocol.

Cardiac effects of echinocandins after central venous administration in adult rats

Echinocandins have become the agents of choice for early and specific antifungal treatment in critically ill patients. In vitro studies and clinical case reports revealed a possible impact of echinocandin treatment on cardiac function. The aim of our study was to evaluate echinocandin-induced cardiac failure. Using an in vivo rat model, we assessed hemodynamic parameters and time to hemodynamic failure after central venous application (vena jugularis interna) of anidulafungin (low-dose group, 2.5 mg/kg body weight [BW]; high-dose group, 25 mg/kg BW), caspofungin (low-dose group, 0.875 mg/kg BW; high-dose group, 8.75 mg/kg BW), micafungin (low-dose group, 3 mg/kg BW; high-dose group, 30 mg/kg BW), and placebo (0.9% sodium chloride). Left ventricular heart tissue was collected to determine mitochondrial enzyme activity via spectrophotometric measurements. mRNA expression of transcriptional regulators and primary mitochondrial transcripts, mitochondrial DNA (mtDNA) content, and citrate synthase activity were also explored. Animals receiving high-dose anidulafungin or caspofungin showed an immediate decrease in hemodynamic function. All of the subjects in these groups died during the observation period. Every animal in the untreated control group survived (P < 0.001). Hemodynamic failure was not noticed in the anidulafungin and caspofungin low-dose groups. Micafungin had no impact on cardiac function. In analyzing mitochondrial enzyme activity and mitochondrial transcripts, we found no association between echinocandin administration and the risk for hemodynamic failure. Further experimental studies are needed to elucidate the underlying mechanisms involved in cardiotoxic echinocandin effects. In addition, randomized controlled clinical trials are needed to explore the clinical impact of echinocandin treatment in critically ill patients.

Reversible dilated cardiomyopathy associated with amphotericin B therapy

WHAT IS KNOWN AND OBJECTIVE

Amphotericin B (AmB) is commonly used to treat a broad spectrum of fungal infections and leishmaniasis. Its use is limited by numerous adverse effects. Reversible dilated cardiomyopathy associated with AmB is a rare disorder with only four previously reported cases, and all of them referring to patients who presented with a predisposing factor for heart failure.

CASE SUMMARY

A previously healthy 45-year-old man with visceral leishmaniasis treated with AmB developed acute dilated cardiomyopathy. Other causes of heart failure as well-known predisposing factors for this condition were ruled out. As with previously reported cases, the cardiac function of our patient returned to normal shortly after.

WHAT IS NEW AND CONCLUSION

We describe the first case of dilated cardiomyopathy associated with the administration of AmB in a patient without any known predisposing factor for developing cardiac dysfunction. Available evidence suggests that AmB may induce cardiotoxicity. Further investigations are needed to clarify this issue.