Cardiotoxic Effect of Modern Anthracycline Dosing on Left Ventricular Ejection Fraction: A Systematic Review and Meta-Analysis of Placebo Arms From Randomized Controlled Trials

Redefining anthracycline-related subclinical cardiotoxicity: 'Absolute' and 'relative' change in longitudinal strain

AIMS

Anthracycline chemotherapy (AC) for breast cancer can cause cancer therapy-related cardiac dysfunction (CTRCD) with resultant heart failure, traditionally defined as a reduction in left ventricular (LV) ejection fraction on echocardiography. In recent years, global longitudinal systolic strain (GLS) has been used to identify subclinical cardiac dysfunction prior to development of overt CTRCD. Recent harmonized guidelines have incorporated GLS into definitions for CTRCD to identify cardiac dysfunction and inform decisions regarding cardioprotective strategies.

METHODS AND RESULTS

We evaluated subclinical dysfunction in breast cancer patients treated with AC and determined the echocardiographic and patient factors associated with significant GLS changes. One hundred fourteen HER2 negative patients treated with AC were prospectively recruited and underwent serial echocardiograms (LVEF and LVGLS) at three time points (prior to AC, 3 months, and 1 year). CTRCD was defined as an asymptomatic reduction in LVEF of 10% or symptomatic drop of 5% to LVEF <53%. Subclinical LV dysfunction was defined as a reduction of ≥10% in GLS compared with baseline, recognizing that this cut off identified an 'at risk cohort' rather than patients with established CTRCD. No participant demonstrated CTRCD by reduction in LVEF. Forty-three patients (38%) demonstrated a ≥10% relative reduction in GLS at 12 months; 20/43 (47%) had a reduced absolute GLS to <16%, and were older, had hypertension, increased LV mass, lower baseline e' velocity and GLS. GLS ≥20.5% at baseline yielded a sensitivity of 79% and specificity of 87% for a normal GLS (i.e., ≥16%) at 1 year despite a ≥10% reduction from baseline.

CONCLUSIONS

We present a stepwise evaluation for subclinical LV dysfunction using both a relative reduction in GLS combined with an absolute reduction in GLS. We believe our findings may re-stratify patients with a high baseline GLS into a lower risk group despite transient relative GLS decrements ≥10%.

Left ventricular mechanical dyssynchrony after chemotherapy in breast cancer patients with normal rest gated SPECT-MPI

OBJECTIVES

Early diagnosis of chemotherapy-induced cardiotoxicity plays an important role in preventing heart failure. The main aim of our study was to assess left ventricular (LV) dyssynchrony measured by phase analysis of gated single-photon emission computed tomography (SPECT) as an early sign of cardiotoxicity after breast cancer chemotherapy.

METHODS

This cross-sectional study was conducted on patients with stage ≤ 3 breast cancer and no history of cardiovascular disease or diabetes. After mastectomy, the patients underwent rest gated SPECT myocardial perfusion imaging (MPI). Sixty patients with normal gated SPECT-MPI were selected and the imaging was performed after chemotherapy with doxorubicin, cyclophosphamide and paclitaxel. LV function and contractility parameters were extracted by QGS software and the results were compared with the t test method. The abnormality of at least one of the three phase analysis indices was considered as left ventricular dyssynchrony (LVD).

RESULTS

The average LV end-systolic volume and ejection fraction (LVEF) before and after chemotherapy were (16.2 ± 8.0 ml and 21.6 ± 11.6 ml) and (73.4 ± 7.9% and 67.5 ± 9.2%) respectively, which showed a significant decrease (P < 0.05). In 2 patients (3.3%), the LVEF decreased to less than 50% after chemotherapy. The average parameters of left ventricular contractility before and after chemotherapy were, respectively, as follows: PHB (24.1 ± 7.5 and 33.8 ± 16.4), PSD (9.4 ± 6.1 and 5.7 ± 1.9) and entropy (28.9 ± 7.1 and 35.6 ± 9.7), which showed a significant increase (P < 0.05). LVD was observed in 14 patients (23.4%) after chemotherapy and prevalence of LVD was significantly higher in patients who had received a cumulative dose of doxorubicin of more than 400 mg/m2 (P = 0.005). There was no relationship between age and body mass index with the incidence of LVD after chemotherapy (P > 0.05).

CONCLUSION

Using phase analysis of gated SPECT-MPI, chemotherapy-induced LVD was seen in a significant number of patients with breast cancer, especially with a high cumulative dose of doxorubicin. LVD might indicate chemotherapy-induced cardiotoxicity before LVEF becomes abnormal.

Diastolic function assessment with left atrial strain in long-term survivors of childhood acute lymphoblastic leukemia

INTRODUCTION AND OBJECTIVES

Survivors of childhood cancer might be at increased risk of diastolic dysfunction at follow-up due to exposure to cardiotoxic treatment. Although assessment of diastolic function is challenging in this relatively young population, left atrial strain might provide a novel insight in this evaluation. Our aim was to examine diastolic function in a cohort of long-term survivors of childhood acute lymphoblastic leukemia by using left atrial strain and conventional echocardiographic parameters.

METHODS

Long-term survivors who were diagnosed at a single center between 1985 and 2015 and a control group of healthy siblings were recruited. Conventional diastolic function parameters and atrial strain were compared, and the latter was measured during the 3 atrial phases: reservoir (PALS), conduit (LACS) and contraction (PACS). Inverse probability of treatment weighting was used to account for differences between the groups.

RESULTS

We analyzed 90 survivors (age, 24.6±9.7 years, time since diagnosis 18 [11-26] years) and 58 controls. PALS and LACS were significantly reduced compared with the control group: 46.4±11.2 vs 52.1±11.7; P=.003 and 32.5±8.8 vs 38.2±9.3; P=.003, respectively. Conventional diastolic parameters and PACS were similar between the groups. The reductions in PALS and LACS were associated with exposure to cardiotoxic treatment in age- and sex-adjusted analysis (≥ moderate risk, low risk, controls): 45.4±10.5, 49.5±12.9, 52.1±11.7; Padj=.003, and 31.7±9.0, 35.2±7.5, 38.2±9.3; Padj=.001, respectively.

CONCLUSIONS

Long-term childhood leukemia survivors showed a subtle impairment of diastolic function that was detected with atrial strain but not with conventional measurements. This impairment was more pronounced in those with higher exposure to cardiotoxic treatment.

Superiority of left heart deformation in early anthracycline-related cardiac dysfunction detection

OBJECTIVE

This study aimed to assess the incidence of early cancer therapy-related cardiac dysfunction (CTRCD) and the characteristics of left and right heart deformations during anthracycline chemotherapy.

METHODS

We prospectively enrolled a cohort of 351 chemotherapy-naïve women with breast cancer and cardiovascular risk factors who were scheduled to receive anthracycline. The left ventricular ejection fraction (LVEF), left ventricular global longitudinal strain (LV-GLS) and right ventricular and left atrial longitudinal strains were evaluated using echocardiography at baseline, before every subsequent cycles and at 3 weeks after the final anthracycline dose. CTRCD was defined as a new LVEF reduction by ≥10 percentage points to an LVEF<50% and/or a new relative decline in GLS by >15% from the baseline value.

RESULTS

Eighteen (5.1%) patients had evidence of asymptomatic CTRCD during anthracycline treatment, and 50% developed CTRCD before completing the chemotherapy regimen. In the CTRCD group, while LV-GLS decrease significantly after the first dose of anthracycline, the reduction of right ventricular free-wall longitudinal strain and left atrial reservoir strain were observed after the second dose. Other strain indices could not be used to identify early CTRCD.

CONCLUSIONS

Cardiotoxicity appeared soon after the initiation of anthracycline chemotherapy. Among the left-heart and right-heart mechanics, LV-GLS remains the best deformation indicator for detecting early CTRCD.

Impaired Cardiac and Skeletal Muscle Energetics Following Anthracycline Therapy for Breast Cancer

BACKGROUND

Anthracycline-related cardiac toxicity is a recognized consequence of cancer therapies. We assess resting cardiac and skeletal muscle energetics and myocyte, sarcomere, and mitochondrial integrity in patients with breast cancer receiving epirubicin.

METHODS

In a prospective, mechanistic, observational, longitudinal study, we investigated chemotherapy-naive patients with breast cancer receiving epirubicin versus sex- and age-matched healthy controls. Resting energetic status of cardiac and skeletal muscle (phosphocreatine/gamma ATP and inorganic phosphate [Pi]/phosphocreatine, respectively) was assessed with 31P-magnetic resonance spectroscopy. Cardiac function and tissue characterization (magnetic resonance imaging and 2D-echocardiography), cardiac biomarkers (serum NT-pro-BNP and high-sensitivity troponin I), and structural assessments of skeletal muscle biopsies were obtained. All study assessments were performed before and after chemotherapy.

RESULTS

Twenty-five female patients with breast cancer (median age, 53 years) received a mean epirubicin dose of 304 mg/m2, and 25 age/sex-matched controls were recruited. Despite comparable baseline cardiac and skeletal muscle energetics with the healthy controls, after chemotherapy, patients with breast cancer showed a reduction in cardiac phosphocreatine/gamma ATP ratio (2.0±0.7 versus 1.1±0.5; P=0.001) and an increase in skeletal muscle Pi/phosphocreatine ratio (0.1±0.1 versus 0.2±0.1; P=0.022). This occurred in the context of increases in left ventricular end-systolic and end-diastolic volumes (P=0.009 and P=0.008, respectively), T1 and T2 mapping (P=0.001 and P=0.028, respectively) but with preserved left ventricular ejection fraction, mass and global longitudinal strain, and no change in cardiac biomarkers. There was preservation of the mitochondrial copy number in skeletal muscle biopsies but a significant increase in areas of skeletal muscle degradation (P=0.001) in patients with breast cancer following chemotherapy. Patients with breast cancer demonstrated a reduction in skeletal muscle sarcomere number from the prechemotherapy stage compared with healthy controls (P=0.013).

CONCLUSIONS

Contemporary doses of epirubicin for breast cancer treatment result in a significant reduction of cardiac and skeletal muscle high-energy 31P-metabolism alongside structural skeletal muscle changes.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04467411.

Multimodal Imaging of Cancer Therapy-Related Cardiac Dysfunction in Breast Cancer-A State-of-the-Art Review

BACKGROUND

This review focuses on multimodality imaging of cardiotoxicity in cancer patients, with the aim of evaluating the effectiveness of different techniques in detecting and monitoring cardiac changes associated with cancer therapy.

METHODS

Eight studies were included in the review, covering various imaging modalities such as cardiac magnetic resonance imaging, echocardiography, and multigated acquisition scanning.

RESULTS

Cardiac magnetic resonance imaging emerged as the most definitive modality, offering real-time detection, comprehensive assessment of cardiac function, the ability to detect early myocardial changes, and superior detection of cardiotoxicity when compared to the other imaging modalities. The studies also emphasize the importance of parameters such as left ventricular ejection fraction and global longitudinal strain in assessing cardiac function and predicting cardiotoxicity.

CONCLUSION

Due to the common use of HER2 agents and anthracyclines within the breast cancer population, the LVEF as a critical prognostic measurement for assessing heart health and estimating the severity of left-sided cardiac malfunction is a commonly used endpoint. CTRCD rates differed between imaging modalities, with cardiac MRI the most sensitive. The use of multimodal cardiac imaging remains a nuanced area, influenced by local availability, the clinical question at hand, body habits, and medical comorbidities. All of the imaging modalities listed have a role to play in current care; however, focus should be given to increasing the provision of cardiac MRI for breast cancer patients in the future to optimize the detection of CTRCD and patient outcomes thereafter.

Promoter Optimization Circumvents Bcl-2 Transgene-Mediated Suppression of Lentiviral Vector Production

Lentiviral vectors are a robust gene delivery tool for inducing transgene expression in a variety of cells. They are well suited to facilitate the testing of therapeutic candidate genes in vitro, due to relative ease of packaging and ability to transduce dividing and non-dividing cells. Our goal was to identify a gene that could be delivered to the heart to protect against cancer-therapy-induced cardiotoxicity. We sought to generate a lentivirus construct with a ubiquitous CMV promoter driving expression of B-cell lymphocyte/leukemia 2 gene (Bcl-2), a potent anti-apoptotic gene. Contrary to our aim, overexpression of Bcl-2 induced cell death in the producer HEK293T cells, resulting in failure to produce usable vector titre. This was circumvented by exchanging the CMV promoter to the cardiac-specific NCX1 promoter, leading to the successful production of a lentiviral vector which could induce cardioprotective expression of Bcl-2. In conclusion, reduced expression of Bcl-2 driven by a weaker promoter improved vector yield, and led to the production of functional cardioprotective Bcl-2 in primary cardiomyocytes.

Baseline Troponin Level and Cardiac Toxicity in HER2-positive Early Breast Cancer Patients Receiving Trastuzumab

BACKGROUND/AIM

There is controversy around the use of high-sensitive troponin T (hs-TnT) as an early biomarker of cardiac toxicity in patients with breast cancer on trastuzumab (T).

PATIENTS AND METHODS

Patients receiving adjuvant or neo-adjuvant T for early HER2-positive breast cancer were prospectively included. Transthoracic echocardiograms and matched hs-TnT before T and at 3, 6, and 9 months were performed on all patients. Congestive heart failure, cardiac death, a decline in left ventricular ejection fraction (LVEF) of more than 10% from baseline even if it is still within the normal range, or a drop in LVEF below 55% were all considered signs of cardiac toxicity.

RESULTS

In total, 24 patients (median age: 57; range=39-79 years) were enrolled. Anthracyclines were administered to all patients but three as part of neo/adjuvant treatment before T. Cardiovascular toxicity was observed in 3 out of 24 (12.5%) patients: two non-symptomatic LVEF declines (8.3%) and one heart failure episode (4.2%). In the entire population, the mean baseline hs-TnT level was 10.1±8.8 pg/ml, and after 3, 6, and 12 months, no appreciable change was observed. Patients with cardiac toxicity had mean hs-TnT levels higher than those without (18.3±12.3 vs. 8.2±7.2 pg/ml; p=0.049). A definite trend was evident in the chi-square test (chi2=3.52; p=0.06).

CONCLUSION

In anthracycline-exposed patients with early breast cancer, hs-TnT may be able to identify those at risk of developing cardiac toxicity during neo/adjuvant T treatment.

Effects of exercise training on cardiac toxicity markers in women with breast cancer undergoing chemotherapy with anthracyclines: a randomized controlled trial

AIMS

Exercise training has been suggested to prevent anthracycline-related cardiac dysfunction, but clinicalbased evidence is scarce. We investigated the effects of a supervised exercise training programme (SETP) on cardiac toxicity markers in women with breast cancer (BC) receiving anthracycline-containing chemotherapy.

METHODS AND RESULTS

Ninety-three women with early-stage breast cancer were randomly allocated to a supervised exercise training programme (SETP) plus usual care group (Exercise, n = 47) or usual care alone group (UC, n = 46). The SETP consisted of three sessions per week, combining aerobic and resistance training, conducted concurrently across the anthracycline-containing chemotherapy length. The primary endpoint was the change in left ventricular ejection fraction (LVEF) from baseline to the end of anthracycline cycles. Secondary endpoints included global longitudinal strain (GLS) and other conventional echocardiographic parameters, cardiorespiratory fitness (estimated peak VO2), circulating biomarkers (NT-proBNP, hs-TnT), and safety of the SETP. The study endpoints were also assessed 3 months after the end of anthracycline cycles. All patients were prescribed four cycles of doxorubicin plus cyclophosphamide (AC). No significant between-group differences in LVEF change were seen at the end of AC [mean difference: 0.7%; 95% confidence interval (CI): -0.8, 2.3; P = 0.349] and 3 months after AC (1.1%; 95% CI: -0.5, 2.6; P = 0.196). Compared to the usual care (UC) group, the estimated peak VO2 increased in the Exercise group at the end of AC (1.6 mL O2·kg-1·min-1; 95% CI: 0.06, 3.1; P = 0.041) and 3 months after AC (3.1 mL O2·kg-1·min-1; 95% CI: 1.4, 4.7; P < 0.001). No between-group differences were found in the remaining secondary endpoints. No serious adverse events were observed during SETP.

CONCLUSION

Exercise training was safe during chemotherapy and significantly improved cardiorespiratory fitness. No significant effects were seen on cardiac toxicity markers (LVEF or GLS) as compared to the usual care.

TRIAL REGISTRATION

Mama Move Gaia on treatment trial ISRCTN32617901.

Cardiac magnetic relaxometry versus ejection fraction in anthracycline-related cardiac changes: a systematic review and meta-analysis

PURPOSE

The purpose of this meta-analysis is to compare the magnitude of the changes in left ventricular ejection fraction (LVEF) and cardiac magnetic resonance (CMR) relaxometry techniques soon after the completion of anthracycline therapy. Anthracyclines are associated with myocardial functional and morphological changes. LVEF is currently used to identify the functional changes. Anthracyclines can also cause myocardial inflammation and oedema. This can be assessed using CMR relaxometry techniques; T1 and T2 mapping and extracellular volume (ECV) fraction.

METHODS

Three databases were systematically searched for studies evaluating CMR relaxometry parameter at baseline and 1±1 months after anthracycline completion (the last search date 17 March 2023). CMR parameters pre and post anthracycline-based chemotherapy were abstracted. A random effects model was used to pool mean difference (MD) in LVEF and ECV. Standardised mean difference (SMD) was also calculated for T1 and T2 mapping due to the variations in techniques, normal ranges and for the comparison among the parameters.

RESULTS

A total of 296 patients were included from 10 studies. 84% were female with a mean age of 54.9 years. Statistically significant alterations were observed in LVEF (MD -3.38% (95% CI -5.13%, -1.62%)) and ECV (1.92% (1.30%, 2.53%)). The pooled SMDs were also significant in LVEF, T1, T2 and ECV with -0.61 (-0.91, -0.30), 0.53 (0.16, 0.90), 0.59 (0.22, 0.96) and 0.74 (0.41, 1.06), respectively.

CONCLUSIONS

Our meta-analysis demonstrated small but significant alterations in CMR relaxometry parameters soon after anthracycline therapy, where ECV was superior to LVEF and T1 or T2 mapping. However, these short-term MDs were below the minimal detectable differences.

PROSPERO REGISTRATION NUMBER

CRD42020196296.

Comparing Renin-Angiotensin-Aldosterone Blockade Regimens for Long-Term Chemotherapy-Related Cardiac Dysfunction: A Network Meta-Analysis

PURPOSE

Cancer therapies including trastuzumab and anthracyclines are cardiotoxic and cause cardiac dysfunction. To prevent cardiotoxicity, pharmacological agents used in heart failure have been administered concomitantly with cardiotoxic cancer therapy, but few studies to date have performed a head-to-head comparison of these different agents. This systematic review and network meta-analysis of randomized-controlled trials aims to evaluate the efficacy of renin-angiotensin-aldosterone system (RAAS) blockers, namely angiotensin-converting enzyme inhibitors (ACE-Is), aldosterone receptor blockers (ARBs), and mineralocorticoid receptor antagonists (MRAs), in primary prevention against chemotherapy-related cardiac dysfunction in patients receiving anthracyclines and/or trastuzumab.

METHODS

A systematic search was performed in major web databases for studies from inception to 15 September 2022. A Bayesian network meta-analysis model was used to assess the relative effects of competing treatments on the primary outcomes of risk of significant decline in left ventricular ejection fraction (LVEF) and mean LVEF decline. Secondary outcomes included left ventricular diastolic function, global longitudinal strain, and cardiac biomarkers. This study is registered with PROSPERO, CRD42022357980.

RESULTS AND CONCLUSION

Nineteen studies reported the effects of 13 interventions (N = 1905 patients). Only enalapril (RR 0.05, 95% CI 0.00-0.20) was associated with reduced risk of patients developing significant decline in LVEF relative to placebo. Subgroup analysis showed that the beneficial effect of enalapril was driven by protection against anthracycline-associated toxicity. In addition, no RAAS-inhibiting agents showed efficacy in protection against treatment with both anthracycline and trastuzumab. The use of RAAS inhibition therapy did not conclusively impact on other markers of cardiac function, including left ventricular diastolic function and cardiac biomarkers.

Efficacy and safety of cardioprotective drugs in chemotherapy-induced cardiotoxicity: an updated systematic review & network meta-analysis

BACKGROUND

Cancer patients receiving chemotherapy have an increased risk of cardiovascular complications. This limits the widespread use of lifesaving therapies, often necessitating alternate lower efficacy regimens, or precluding chemotherapy entirely. Prior studies have suggested that using common cardioprotective agents may attenuate chemotherapy-induced cardiotoxicity. However, small sample sizes and conflicting outcomes have limited the clinical significance of these results.

HYPOTHESIS

A comprehensive network meta-analysis using updated and high-quality data can provide more conclusive information to assess which drug or drug class has the most significant effect in the management of chemotherapy-induced cardiotoxicity.

METHODS

We performed a literature search for randomized controlled trials (RCTs) investigating the effects of cardioprotective agents in patients with chemotherapy-induced cardiotoxicity. We used established analytical tools (netmeta package in RStudio) and data extraction formats to analyze the outcome data. To obviate systematic bias in the selection and interpretation of RCTs, we employed the validated Cochrane risk-of-bias tools. Agents included were statins, aldosterone receptor antagonists (MRAs), ACEIs, ARBs, and beta-blockers. Outcomes examined were improvement in clinical and laboratory parameters of cardiac function including a decreased reduction in left ventricular ejection fraction (LVEF), clinical HF, troponin-I, and B-natriuretic peptide levels.

RESULTS

Our study included 33 RCTs including a total of 3,285 patients. Compared to control groups, spironolactone therapy was associated with the greatest LVEF improvement (Mean difference (MD) = 12.80, [7.90; 17.70]), followed by enalapril (MD = 7.62, [5.31; 9.94]), nebivolol (MD = 7.30, [2.39; 12.21]), and statins (MD = 6.72, [3.58; 9.85]). Spironolactone was also associated with a significant reduction in troponin elevation (MD =  - 0.01, [- 0.02; - 0.01]). Enalapril demonstrated the greatest BNP reduction (MD =  - 49.00, [- 68.89; - 29.11]), which was followed by spironolactone (MD =  - 16.00, [- 23.9; - 8.10]). Additionally, patients on enalapril had the lowest risk of developing clinical HF compared to the control population (RR = 0.05, [0.00; 0.75]).

CONCLUSION

Our analysis reaffirmed that statins, MRAs, ACEIs, and beta-blockers can significantly attenuate chemotherapy-induced cardiotoxicity, while ARBs showed no significant effects. Spironolactone showed the most robust improvement of LVEF, which best supports its use among this population. Our analysis warrants future clinical studies examining the cardioprotective effects of cardiac remodeling therapy in cancer patients treated with chemotherapeutic agents.

Heart Failure Association-International Cardio-Oncology Society Risk Score Validation in HER2-Positive Breast Cancer

BACKGROUND

This paper looks to validate the risk score from the Heart Failure Association of the European Society of Cardiology and the International Cardio-Oncology Society (HFA-ICOS) for predicting potential cardiotoxicity from anticancer therapy for patients positive for human epidermal growth factor receptor 2.

METHODS

A total of 507 patients with at least five years since index diagnosis of breast cancer were retrospectively divided according to the HFA-ICOS risk proforma. According to level of risk, these groups were assessed for rates of cardiotoxicity via mixed-effect Bayesian logistic regression model.

RESULTS

A follow-up of five years observed cardiotoxicity of 3.3% (n = 3) in the low-risk, 3.3% (n = 10) in the medium-risk, 4.4% (n = 6) in the high-risk, and 38% (n = 6) in the very-high-risk groups respectively. For cardiac events related to treatment, the risk was significantly higher for the very-high-risk category of HFA-ICOS compared to other categories (Beta = 3.1, 95% CrI: 1.5, 4.8). For overall cardiotoxicity related to treatment, the area under the curve was 0.643 (CI 95%: 0.51, 0.76), with 26.1% (95% CI: 8%, 44%) sensitivity and 97.9% (95% CI: 96%, 99%) specificity.

CONCLUSIONS

The HFA-ICOS risk score has moderate power in predicting cancer therapy-related cardiotoxicity in HER2-positive breast cancer patients.

Quantification of Extracellular Volume in CT in Neoadjuvant Chemotherapy in Breast Cancer: New Frontiers in Assessing the Cardiotoxicity of Anthracyclines and Trastuzumab

Breast cancer patients undergoing neoadjuvant chemotherapy with anthracyclines or trastuzumab can suffer cardiotoxic issues. Nowadays, the markers of cardiac damage are still not reliable, and extracellular volume (ECV) calculated from CT could be a promising cardiotoxic marker. Eighty-two patients, treated with two different chemotherapy regimens based on doxorubicin (DOX) or epirubicin-trastuzumab (EPI-TRAS), were retrospectively selected and the variations in extracellular volume (ECV) values were measured and analyzed. Whole Body CT (WB-CT) scans were acquired after 1 min, in the portal phase (PP), and after 5 min, in the delayed phases (DP), at the baseline (T₀), after one year (T₁) and after five years (T₅) from the end of chemotherapies. The values measured by two radiologists with different levels of experience were evaluated in order to assess the inter-reader reproducibility assessment (ICC = 0.52 for PP and DP). Further, we performed a population-based analysis and a drug-oriented subgroup analysis in 54 DOX-treated and 28 EPI-TRAS-treated patients. In the general cohort of women treated with any of the two drugs, we observed in the lapse T₀-T₁ a relative increase (RI) of 25% vs. 20% (PP vs. DP, p < 0.001) as well as in the lapse T₀-T₅ an RI of 17% vs. 15% (PP vs. DP, p < 0.01). The DOX-treated patients reported in the lapse T₀-T₁ an RI of 22% (p < 0.0001) in PP and an RI of 16% (p = 0.018) in the DP, with ECV values remaining stably high at T₅ both in PP (RI 14.0%, p < 0.0001) and in DP (RI 17%, p = 0.005) highlighting a possible hallmark of a persisting CTX sub-damage. On the other hand, ECV measured in EPI-TRAS-treated women showed an RI in T₀-T₁ of 18% (p = 0.001) and 29% (p = 0.006) in PP and DP, respectively, but the values returned to basal levels in T₅ both in the PP (p = 0.12) and in DP setting (p = 0.13), suggesting damage in the first-year post-treatment and a possible recovery over time. For the 82 patients, an echocardiography was performed at T₀, T₁= 12 m + 3 m and T₅ = 60 m + 6 m with LVEF values at T₀ (64% ± 5%), T₁ (54% ± 6%) and T₅ (53% ± 8%). WB-CT-derived ECV values could provide a valid imaging marker for the early diagnosis of cardiotoxic damage in BC patients undergoing oncological treatments. We detected different patterns during the follow-up, with stably high values for DOX, whereas EPI-TRAS showed a peak within the first year, suggesting different mechanisms of cardiac damage.

Upcycling the anthracyclines: New mechanisms of action, toxicology, and pharmacology

The anthracyclines are a family of natural products isolated from soil bacteria with over 2000 chemical representatives. Since their discovery seventy years ago by Waksman and co-workers, anthracyclines have become one of the best-characterized anticancer chemotherapies in clinical use. The anthracyclines exhibit broad-spectrum antineoplastic activity for the treatment of a variety of solid and liquid tumors, however, their clinical use is limited by their dose-limiting cardiotoxicity. In this review article, we discuss the toxicity of the anthracyclines on several organ systems, including new insights into doxorubicin-induced cardiotoxicity. In addition, we discuss new medicinal chemistry developments in the biosynthesis of new anthracycline analogs and the synthesis of new anthracycline analogs with diminished cardiotoxicity. Lastly, we review new studies that describe the repurposing of the anthracyclines, or "upcycling" of the anthracyclines, as anti-infective agents, or drugs for niche indications. Altogether, the anthracyclines remain a mainstay in the clinic with a potential new "lease on life" due to deeper insight into the mechanism underlying their cardiotoxicity and new developments into potential new clinical indications for their use. Keywords: Anthracycline, chemotherapy, toxicology, medicinal chemistry, biosynthesis.

Natural Progression of Left Ventricular Function following Anthracyclines without Cardioprotective Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

Anthracyclines form the backbone of many systemic chemotherapy regimens but are accompanied by dose-limiting cardiotoxicity. We elucidate the progression and severity of cardiac function over time, in the absence of cardioprotection, which less is known about.

METHODS

This PRISMA-guideline-adherent review was registered on PROSPERO (CRD42022373496).

RESULTS

26 studies met the eligibility criteria including a total of 910 patients. The overall reduction in post-anthracycline pooled mean left ventricular ejection fraction (LVEF) in placebo arms of the included randomised-controlled trials was 4.5% (95% CI, 2.6 to 6.4). The trend in LVEF showed a progressive decline until approximately 180 days, after which there was no significant change. Those receiving a cumulative anthracycline dose of 300 mg/m2 experienced a more profound reduction. The overall pooled risk of a 10% absolute decline in LVEF from baseline, or a decline to an LVEF below 50%, was 17% (95% CI: 11 to 24; I2 = 71%). Sensitivity analyses of baseline LVEF and trastuzumab treatment status did not yield significant differences.

CONCLUSION

While the mean LVEF decline in patients without cardioprotective therapy was clinically small, a vulnerable subset experienced significant impairment. Further research to best identify those who benefit most from cardioprotective therapies when receiving anthracyclines is required.

RGD_PLGA Nanoparticles with Docetaxel: A Route for Improving Drug Efficiency and Reducing Toxicity in Breast Cancer Treatment

Breast cancer is the leading cause of cancer-related death in women. Although many therapeutic approaches are available, systemic chemotherapy remains the primary choice, especially for triple-negative and advanced breast cancers. Unfortunately, systemic chemotherapy causes serious side effects and requires high doses to achieve an effective concentration in the tumor. Thus, the use of nanosystems for drug delivery may overcome these limitations. Herein, we formulated Poly (lactic-co-glycolic acid) nanoparticles (PLGA-NPs) containing Docetaxel, a fluorescent probe, and a magnetic resonance imaging (MRI) probe. The cyclic RGD tripeptide was linked to the PLGA surface to actively target α_vβ₃ integrins, which are overexpressed in breast cancer. PLGA-NPs were characterized using dynamic light scattering, fast field-cycling ¹H-relaxometry, and ¹H-nuclear magnetic resonance. Their therapeutic effects were assessed both in vitro in triple-negative and HER2+ breast cancer cells, and in vivo in murine models. In vivo MRI and inductively coupled plasma mass spectrometry of excised tumors revealed a stronger accumulation of PLGA-NPs in the RGD_PLGA group. Targeted PLGAs have improved therapeutic efficacy and strongly reduced cardiac side effects compared to free Docetaxel. In conclusion, RGD-PLGA is a promising system for breast cancer treatment, with positive outcome in terms of therapeutic efficiency and reduction in side effects.

Rationale and Design of the Cardiac CARE Trial: A Randomized Trial of Troponin-Guided Neurohormonal Blockade for the Prevention of Anthracycline Cardiotoxicity

BACKGROUND

Anthracyclines are effective cytotoxic drugs used in the treatment of breast cancer and lymphoma but are associated with myocardial injury, left ventricular dysfunction, and heart failure. Anthracycline-induced cardiotoxicity is highly variable in severity and without a proven therapeutic intervention. β-Adrenergic receptor blockers and renin-angiotensin-system inhibitor therapies have been associated with modest cardioprotective effects in unselected patients.

METHODS

The Cardiac CARE trial is a multicentre prospective randomized open-label blinded end point trial of combination β-adrenergic receptor blocker and renin-angiotensin-system inhibitor therapy in patients with breast cancer and non-Hodgkin lymphoma receiving anthracycline chemotherapy that is associated with myocardial injury. Patients at higher risk of cardiotoxicity with plasma high-sensitivity cTnI (cardiac troponin I) concentrations in the upper tertile at the end of chemotherapy are randomized to standard of care plus combination candesartan and carvedilol therapy or standard of care alone. All patients undergo cardiac magnetic resonance imaging before and 6 months after anthracycline treatment. The primary end point is the change in left ventricular ejection fraction at 6 months after chemotherapy. In low-risk nonrandomized patients, left ventricular ejection fraction before and 6 months after anthracycline will be compared with define the specificity of the high-sensitivity cTnI assay for identifying low-risk participants who do not develop left ventricular systolic dysfunction.

DISCUSSION

Cardiac CARE will examine whether cardiac biomarker monitoring identifies patients at risk of left ventricular dysfunction following anthracycline chemotherapy and whether troponin-guided treatment with combination candesartan and carvedilol therapy prevents the development of left ventricular dysfunction in these high-risk patients.

Role of Myocardial Strain Imaging in Cancer Therapy-Related Cardiac Dysfunction

PURPOSE OF REVIEW

This review aims to provide a contemporary perspective on the role of myocardial strain imaging in the management of patients on cardiotoxic therapy.

RECENT FINDINGS

Risk/benefit evaluation of cardiotoxic cancer treatment remains challenging, weighing life-saving cancer therapy with fatal cardiac dysfunction potentially caused by cancer therapy. The serial change in left ventricular ejection fraction (LVEF) was conventionally used for the detection of cancer therapy-related cardiac dysfunction (CTRCD). Peak systolic global longitudinal strain (GLS) by speckle-tracking echocardiography has turned into a vital pre- and post-chemotherapy assessment for the early detection of cardiotoxicity. Complexity in cardiotoxic therapy regimen, different definition of CTRCD by LVEF, variations in GLS values, timings, and variable cutoffs make it challenging to standardize the protocol for the detection of CTRCD. GLS > 15% relative reduction from baseline has been widely used. Evidence suggests that GLS could predict early subclinical LV dysfunction, and initiation of cardioprotective therapy led to less decline of LV function. Most of the studies used an echocardiographic endpoint, and the impact of GLS on the long-term clinical outcome is not established. GLS has emerged as a reliable measure to identify early subclinical LV dysfunction by detecting myocardial deformation in patients on cardiotoxic chemotherapy. To date, a significant decline in GLS suggests the initiation of cardioprotective therapy with close monitoring. Interruption of prognostically important cardiotoxic chemotherapies requires a multidisciplinary team approach guided mainly by LVEF and other clinical factors. Further randomized control trials with hard clinical endpoints and longer follow-ups may help to determine the role of GLS in CTRCD.

Long-term effectiveness of empiric cardio-protection in patients receiving cardiotoxic chemotherapies: A systematic review & bayesian network meta-analysis

BACKGROUND

Cardioprotective therapies represent an important avenue to reduce treatment-limiting cardiotoxicities in patients receiving chemotherapy. However, the optimal duration, strategy and long-term efficacy of empiric cardio-protection remains unknown.

METHODS

Leveraging the MEDLINE/Pubmed, CENTRAL and clinicaltrials.gov databases, we identified all randomised controlled trials investigating cardioprotective therapies from inception to November 2021 (PROSPERO-ID:CRD42021265006). Cardioprotective classes included ACEIs, ARBs, Beta-blockers, dexrazoxane (DEX), statins and mineralocorticoid receptor antagonists. The primary end-point was new-onset heart failure (HF). Secondary outcomes were the mean difference in left ventricular ejection fraction (LVEF) change, hypotension and all-cause mortality. Network meta-analyses were used to assess the cardioprotective effects of each therapy to deduce the most effective therapies. Both analyses were performed using a Bayesian random effects model to estimate risk ratios (RR) and 95% credible intervals (95% CrI).

RESULTS

Overall, from 726 articles, 39 trials evaluating 5931 participants (38.0 ± 19.1 years, 72.0% females) were identified. The use of any cardioprotective strategy associated with reduction in new-onset HF (RR:0.32; 95% CrI:0.19-0.55), improved LVEF (mean difference: 3.92%; 95% CrI:2.81-5.07), increased hypotension (RR:3.27; 95% CrI:1.38-9.87) and no difference in mortality. Based on control arms, the number-needed-to-treat for 'any' cardioprotective therapy to prevent one incident HF event was 45, including a number-needed-to-treat of 21 with ≥1 year of therapy. Dexrazoxane was most effective at HF prevention (Surface Under the Cumulative Ranking curve: 81.47%), and mineralocorticoid receptor antagonists were most effective at preserving LVEF (Surface Under the Cumulative Ranking curve: 99.22%).

CONCLUSION

Cardiotoxicity remains a challenge for patients requiring anticancer therapies. The initiation of extended duration cardioprotection reduces incident HF. Additional head-to-head trials are needed.

Prevention of chemotherapy-induced left ventricular dysfunction

Prevention of left ventricular dysfunction predominantly induced by anthracyclines and/or trastuzumab still represents a challenge for cardio-oncology today. Indeed, this complication threatens to limit the significant gain in cancer survival achieved to date. Oncology strategies with cumulative dose limitation, continuous infusion, dexrazoxane, and liposomal formulations have been shown to decrease the risk of anthracycline cardiotoxicity. The preventive use of ace inhibitors, sartans, and/or beta-blockers has not yet provided convincing evidence and the positive effect on left ventricular ejection fraction decline appears poor without a clear clinical relevance. Assessment of the cardiovascular risk profile is a key aspect of the baseline evaluation of any patient scheduled for cancer therapy. Control and/or correction of modifiable cardiovascular risk factors is the first form of primary prevention of cardiotoxicity. It will be necessary to select populations at higher risk of developing cardiac dysfunction, identify patients genetically predisposed to develop cardiotoxicity in order to build the most appropriate strategies to correctly and timely target cardioprotective therapies.

Global Longitudinal Strain Monitoring to Guide Cardioprotective Medications During Anthracycline Treatment

Purpose of the Review

Anthracycline chemotherapy carries a risk of myocardial dysfunction and heart failure even at relatively low doses, and the clinical prediction of cancer treatment-related cardiac dysfunction (CTRCD) is inexact. Careful imaging or biomarker surveillance during chemotherapy can identify CTRCD before the development of heart failure. Currently, this surveillance is performed using ejection fraction (EF). While this is a reliable and reproducible test with three-dimensional techniques, the most widely used imaging technique is two-dimensional echocardiography, for which EF measurements have broad confidence intervals.

Recent Findings

The use of global myocardial strain (GLS) provides a more reliable and reproducible means of assessing global cardiac function and shows meaningful changes before a significant change of EF. Observational studies have shown that although absolute measurements of GLS, both at baseline and during therapy, are predictive of CTRCD risk, the most reliable approach is to assess the change of GLS with therapy — a meaningful relative change of 10–15% being significant. A clinical trial comparing GLS to EF surveillance did not show a significant change of EF in the overall study group, but did show that patients managed with a the GLS-guided approach were less likely to develop a meaningful change of cardiac function to an abnormal level. In at-risk patients, there is good evidence for the protective value of neurohormonal antagonists and statins: the use of GLS enables these benefits to be directed to those most likely to benefit, while minimizing their use in the majority of people, who do not need them.

Summary

Although GLS requires an element of training and efforts to ensure uniformity, it has proven to be a feasible, robust, and reproducible technique, ready for wide adoption.

Potential Applications for Targeted Gene Therapy to Protect Against Anthracycline Cardiotoxicity: JACC: CardioOncology Primer

Anthracyclines are associated with risk of significant dose-dependent cardiotoxicity. Conventional heart failure therapies have neither ameliorated declining cardiac function nor addressed the underlying cause. Gene therapy may confer long-term cardioprotection by rendering the heart resistant to anthracyclines after 1 treatment, although the optimal therapeutic target remains to be elucidated. Recombinant adeno-associated virus is now clinically approved for the treatment of lipoprotein lipase deficiency, spinal muscular atrophy, and hereditary transthyretin amyloidosis. High-throughput methods allow selection of recombinant adeno-associated virus capsids that facilitate efficient gene delivery to specific target cells. Vector safety is enhanced by incorporating cardiac-specific promoters into vector design and localizing delivery to reduce off-target risk. Any cardioprotective transgene may bear a degree of risk as they may play as yet unknown roles, which require careful assessment using clinically relevant models. The innovative technologies outlined here make gene therapy a promising proof of principle, with potential further application to nonanthracycline chemotherapeutics.

•

Protection against anthracycline cardiotoxicity may be achieved by gene delivery to the heart.

•

The optimal cardioprotective target gene remains to be identified.

•

Targeted gene expression in human myocytes can now be achieved with advances in AAV vectorology.

•

It is critical to minimize risk of off-target effects which may impede anthracycline oncotherapy.

Activation of p62-NRF2 Axis Protects against Doxorubicin-Induced Ferroptosis in Cardiomyocytes: A Novel Role and Molecular Mechanism of Resveratrol

Doxorubicin (DOX) is a most common anthracycline chemotherapeutic agent; however, its clinical efficacy is limited due to its severe and irreversible cardiotoxicity. Ferroptosis, characterized by iron overload and lipid peroxidation, plays a pivotal role in DOX-induced cardiotoxicity. Resveratrol (RSV) displays cardioprotective and anticancer effects, owing to its antioxidative and anti-inflammatory properties. However, the role and mechanism of RSV in DOX-mediated ferroptosis in cardiomyocytes is unclear. This study showed that DOX decreased cell viability, increased iron accumulation and lipid peroxidation in H9c2 cells; however, these effects were reversed by RSV and ferroptosis inhibitor ferrostatin-1 (Fer-1) pre-treatment. Additionally, RSV significantly increased the cell viability of H9c2 cells treated with ferroptosis inducers Erastin (Era) and RSL3. Mechanistically, RSV inhibited mitochondrial reactive oxygen species (mtROS) overproduction and upregulated the p62-NRF2/HO-1 pathway. RSV-induced NRF2 activation was partially dependent on p62, and the selective inhibition of p62 (using p62-siRNA interference) or NRF2 (using NRF2 specific inhibitor, ML385) significantly abolished the anti-ferroptosis function of RSV. Furthermore, RSV treatment protected mice against DOX-induced cardiotoxicity, including significantly improving left ventricular function, ameliorating myocardial fibrosis and suppressing ferroptosis. Consistent with in vitro results, RSV also upregulated the p62-NRF2/HO-1 expression, which was inhibited by DOX, in the myocardium. Notably, the protective effect of RSV in DOX-mediated ferroptosis was similar to that of Fer-1 in vitro and in vivo. Thus, the p62-NRF2 axis plays a critical role in regulating DOX-induced ferroptosis in cardiomyocytes. RSV as a potent p62 activator has potential as a therapeutic target in preventing DOX-induced cardiotoxicity via ferroptosis modulation.

Mitochondrial Dynamin-Related Protein Drp1: a New Player in Cardio-oncology

PURPOSE OF REVIEW

This study is aimed at reviewing the recent progress in Drp1 inhibition as a novel approach for reducing doxorubicin-induced cardiotoxicity and for improving cancer treatment.

RECENT FINDINGS

Anthracyclines (e.g. doxorubicin) are one of the most common and effective chemotherapeutic agents to treat a variety of cancers. However, the clinical usage of doxorubicin has been hampered by its severe cardiotoxic side effects leading to heart failure. Mitochondrial dysfunction is one of the major aetiologies of doxorubicin-induced cardiotoxicity. The morphology of mitochondria is highly dynamic, governed by two opposing processes known as fusion and fission, collectively known as mitochondrial dynamics. An imbalance in mitochondrial dynamics is often reported in tumourigenesis which can lead to adaptive and acquired resistance to chemotherapy. Drp1 is a key mitochondrial fission regulator, and emerging evidence has demonstrated that Drp1-mediated mitochondrial fission is upregulated in both cancer cells to their survival advantage and injured heart tissue in the setting of doxorubicin-induced cardiotoxicity. Effective treatment to prevent and mitigate doxorubicin-induced cardiotoxicity is currently not available. Recent advances in cardio-oncology have highlighted that Drp1 inhibition holds great potential as a targeted mitochondrial therapy for doxorubicin-induced cardiotoxicity.

The Protective Effects of Coenzyme Q10 and Lisinopril Against Doxorubicin-Induced Cardiotoxicity in Rats: A Stereological and Electrocardiogram Study

Doxorubicin (DOX) is used as an anticancer drug despite its several side effects, especially its irreversible impacts on cardiotoxicity. Coenzyme Q10 (Q10) as a powerful antioxidant and lisinopril (LIS) as an angiotensin-converting enzyme inhibitor seem to provide protection against DOX-induced cardiotoxicity. Therefore, this study aimed to assess the cardioprotective effects of Q10 and LIS against DOX-induced cardiotoxicity in rats. Adult male Sprague-Dawley rats were randomly assigned into the control, LIS, Q10, DOX, DOX + LIS, and DOX + Q10 groups. On day 21, ECG was recorded and the right ventricle was dissected for evaluation of catalase activity and malondialdehyde (MDA) concentration. Additionally, the left ventricle and the sinoatrial (SA) node were dissected to assess the stereological parameters. The results of ECG indicated bradycardia and increase in QRS duration and QT interval in the DOX group compared to the control group. Meanwhile, the total volumes of the left ventricle, myocytes, and microvessels and the number of cardiomyocyte nuclei decreased, whereas the total volume of the connective tissue and the mean volume of cardiomyocytes increased in the DOX group. On the other hand, the SA node and the connective tissue were enlarged, while the volume of the SA node nuclei was reduced in the DOX group. Besides, catalase activity was lower and MDA concentration was higher in the DOX-treated group. Q10 could recover most stereological parameters, catalase activity, and MDA concentration. LIS also prevented some stereological parameters and ECG changes and improved catalase activity and MDA concentration in the DOX group. The findings suggested that Q10 and LIS exerted cardioprotective effects against DOX-induced cardiac toxicity.

The Utility of Advanced Cardiovascular Imaging in Cancer Patients-When, Why, How, and the Latest Developments

Cardio-oncology encompasses the risk stratification, prognostication, identification and management of cancer therapeutics related cardiac dysfunction (CTRCD). Cardiovascular imaging (CVI) plays a significant role in each of these scenarios and has broadened from predominantly quantifying left ventricular function (specifically ejection fraction) to the identification of earlier bio-signatures of CTRCD. Recent data also demonstrate the impact of chemotherapy on the right ventricle, left atrium and pericardium and highlight a possible role for CVI in the identification of CTRCD through tissue characterization and assessment of these cardiac chambers. This review aims to provide a contemporary perspective on the role of multi-modal advanced cardiac imaging in cardio-oncology.

Kidney Response to Chemotherapy-Induced Heart Failure: mRNA Analysis in Normotensive and Ren-2 Transgenic Hypertensive Rats

The aim of the present study was to perform kidney messenger ribonucleic acid (mRNA) analysis in normotensive, Hannover Sprague-Dawley (HanSD) rats and hypertensive, Ren-2 renin transgenic rats (TGR) after doxorubicin-induced heart failure (HF) with specific focus on genes that are implicated in the pathophysiology of HF-associated cardiorenal syndrome. We found that in both strains renin and angiotensin-converting enzyme mRNA expressions were upregulated indicating that the vasoconstrictor axis of the renin-angiotensin system was activated. We found that pre-proendothelin-1, endothelin-converting enzyme type 1 and endothelin type A receptor mRNA expressions were upregulated in HanSD rats, but not in TGR, suggesting the activation of endothelin system in HanSD rats, but not in TGR. We found that mRNA expression of cytochrome P-450 subfamily 2C23 was downregulated in TGR and not in HanSD rats, suggesting the deficiency in the intrarenal cytochrome P450-dependent pathway of arachidonic acid metabolism in TGR. These results should be the basis for future studies evaluating the pathophysiology of cardiorenal syndrome secondary to chemotherapy-induced HF in order to potentially develop new therapeutic approaches.

Cardiotoxic Effect of Modern Anthracycline Dosing on Left Ventricular Ejection Fraction: A Systematic Review and Meta-Analysis of Placebo Arms From Randomized Controlled Trials

Background

Anthracyclines are a key chemotherapeutic agent used against hematological and solid organ malignancies. However, their benefits in cancer survival are limited by cumulative, dose‐related cardiotoxicity. The impact of anthracyclines on left ventricular ejection fraction (LVEF), in the era of modern chemotherapy regimens, remains unclear.

Methods and Results

Three databases (CENTRAL, MEDLINE, and SCOPUS) were systematically searched for randomized trials evaluating cardioprotective agents against placebo, in preventing cardiotoxicity. Echocardiography or magnetic resonance measured LVEF pre‐ and post‐anthracycline‐based chemotherapy was abstracted from placebo trial arms. The key terms included “anthracycline,” “cardiotoxicity” and “randomized.” A doxorubicin equivalent anthracycline dose metric was calculated to compare different anthracyclines. A random‐effects model was used to pool mean difference in LVEF after anthracycline. Meta‐regressions were calculated to identify variation sources. We included 660 patients from 19 trials. The weighted mean baseline LVEF across studies was 62.6%, and follow‐up LVEF assessment was performed at 6 months. The pooled mean decline in LVEF among placebo arms was 5.4% (95% CI, 3.5%–7.3%) with a doxorubicin equivalent anthracycline dose of 385 mg/m². Meta‐regression analysis showed no significant difference in LVEF against doxorubicin equivalent anthracycline dose as continuous (P=0.29) or against published cut‐offs for cardiotoxicity (250 mg/m², P=0.21; 360 mg/m², P=0.40; and 400 mg/m², P=0.66). The differences in mean LVEF were not associated with sex, adjunct chemotherapy, or cancer type.

Conclusions

The magnitude of LVEF impairment post‐anthracycline therapy appears less than previously described with modern dosing regimens. This may improve the accuracy of power calculation for future clinical trials assessing the role of cardioprotective therapy.