Effects of Paclitaxel and Carboplatin combination on mechanical myocardial and microvascular functions: a transthoracic Doppler echocardiography and two-dimensional strain imaging study

Cardiotoxicity of Chemotherapy: A Multi-OMIC Perspective

Chemotherapy-induced cardiotoxicity is a critical issue in cardio-oncology, as cancer treatments often lead to severe cardiovascular complications. Approximately 10% of cancer patients succumb to cardiovascular problems, with lung cancer patients frequently experiencing arrhythmias, cardiac failure, tamponade, and cardiac metastasis. The cardiotoxic effects of anti-cancer treatments manifest at both cellular and tissue levels, causing deformation of cardiomyocytes, leading to contractility issues and fibrosis. Repeated irradiation and chemotherapy increase the risk of valvular, pericardial, or myocardial diseases. Multi-OMICs analyses reveal that targeting specific pathways as well as specific protein modifications, such as ubiquitination and phosphorylation, could offer potential therapeutic alternatives to current treatments, including Angiotensin converting enzymes (ACE) inhibitors and beta-blockers that mitigate symptoms but do not prevent cardiomyocyte death, highlighting the need for more effective therapies to manage cardiovascular defects in cancer survivors. This review explores the xenobiotic nature of chemotherapy agents and their impact on cardiovascular health, aiming to identify novel biomarkers and therapeutic targets to mitigate cardiotoxicity.

Chemotherapy effect on myocardial fibrosis markers in patients with gynecologic cancer and low cardiovascular risk

BACKGROUND

Patients with gynecologic cancers experience side effects of chemotherapy cardiotoxicity. We aimed to quantify cardiac magnetic resonance (CMR) markers of myocardial fibrosis in patients with gynecologic cancer and low cardiovascular risk who undergo chemotherapy.

METHODS

This study is part of a registered clinical research. CMR T1 mapping was performed in patients with gynecologic cancer and low cardiovascular risk undergoing chemotherapy. The results were compared with those of age-matched healthy control subjects.

RESULTS

68 patients (median age = 50 years) and 30 control subjects were included. The median number of chemotherapy cycles of patients was 9.0 (interquartile range [IQR] 3.3-17.0). Extracellular volume fraction (ECV) (27.2% ± 2.7% vs. 24.5% ± 1.7%, P < 0.001) and global longitudinal strain (-16.2% ± 2.8% vs. -17.4% ± 2.0%, P = 0.040) were higher in patients compared with controls. Patients with higher chemotherapy cycles (>6 cycles) (n=41) had significantly lower intracellular mass indexed (ICMi) compared with both patients with lower chemotherapy cycles (≤6 cycles) (n=27) (median 27.44 g/m2 [IQR 24.03-31.15 g/m2] vs. median 34.30 g/m2 [IQR 29.93-39.79 g/m2]; P = 0.002) and the control group (median 27.44 g/m2 [IQR 24.03-31.15 g/m2] vs. median 32.79 g/m2 [IQR 27.74-35.76 g/m2]; P = 0.002). Patients with two or more chemotherapy regimens had significantly lower ICMi compared with both patients with one chemotherapy regimen (27.45 ± 5.16 g/m2 vs. 33.32 ± 6.42 g/m2; P < 0.001) and the control group (27.45 ± 5.16 g/m2 vs. 33.02 ± 5.52 g/m2; P < 0.001). The number of chemotherapy cycles was associated with an increase in the ECV (Standard regression coefficient [β] = 0.383, P = 0.014) and a decrease in the ICMi (β = -0.349, P = 0.009).

CONCLUSION

Patients with gynecologic cancer and low cardiovascular risk who undergo chemotherapy have diffuse extracellular volume expansion, which is obvious with the increase of chemotherapy cycles. Myocyte loss may be part of the mechanism in patients with a higher chemotherapy load.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn, identifier ChiCTR-DDD-17013450.

The effect of paclitaxel plus carboplatin chemotherapy on subclinical cardiotoxicity in patients with non-small cell lung cancer: A speckle tracking echocardiography-based study

BACKGROUND

Although chemotherapy-induced cardiotoxicity is an emerging problem, limited information is available on the effects of chemotherapy on left ventricular (LV) mechanical functions in patients with non-small cell lung cancer (NSCLC).

OBJECTIVE

We aimed to explore chemotherapy-induced alterations in cardiac mechanical functions in patients with NSCLC using speckle tracking echocardiography (STE).

METHODS

Seventy-one patients with NSCLC and 34 age and sex matched control subjects were consecutively included. Based on their good performance status (Eastern Cooperative Oncology Group performance status), 39 patients were treated with paclitaxel plus carboplatin (PC) regimen and 32 patients were treated with vinorelbine plus cisplatin (VC) regimen. All patients and controls underwent conventional two-dimensional echocardiography and STE at baseline to assess their LV functions. The echocardiographic examinations of NSCLC patients were repeated after the chemotherapy regimens.

RESULTS

None of the NSCLC patients developed any signs or symptoms of clinical heart failure during or after the chemotherapy. There were not any significant differences in LV ejection fraction between NSCLC patients and controls before and after chemotherapy. There were not any significant differences in baseline LV global longitudinal strain (GLS), radial strain (RS), and circumferential strain (CS) between NSCLC patients and controls. However, all LV GLS, RS and CS significantly decreased in patients treated with the PC regimen resulting in a significant difference compared to both VC group and controls while no significant decreases were observed in strain measures in VC group.

CONCLUSION

Paclitaxel plus carboplatin, but not VC, may induce subclinical cardiotoxicity in patients with NSCLC, which may be detected by STE.

Vascular and Cardiac Prognostic Determinants in Patients with Gynecological Cancers: A Six-Year Follow-up Study

Background: The aim of this study was to assess the role of cardiac and vascular parameters as all-cause mortality determinants in patients suffering from gynecological cancers. Methods: This was an observational, prospective, non-randomized, and non-controlled study. Forty-seven consecutive patients (mean age: 58 ± 13 years) were enrolled after cancer staging. All patients underwent evaluation of vascular (common carotid intima-media thickness (mean C-IMT), flow-mediated dilation of the brachial artery (FMD), and antero-posterior diameter of the infrarenal abdominal aorta (APAO)) and cardiac function and morphology before cancer-related interventions. A 6-year follow-up was carried out to assess the overall survival of the whole population. Results: Twenty patients (42%) died by the time of the 6-year follow-up. The brachial artery FMD values were higher in the survivors than the non-survivors (9.71 ± 3.53% vs. 6.13 ± 2.62%, p < 0.001), as well as the LVEF (60.8 ± 3.0% vs. 57.8 ± 4.4%, p = 0.009). There were no differences in the mean C-IMT, APAO, and other echocardiographic parameters. ROC curve analysis identified a baseline LVEF < 57% and FMD value < 5.8% as the best cut-offs. Kaplan–Meier evaluation showed that the LVEF, tricuspid annular plane systolic excursion, and FMD were the best predictors of all-cause mortality, although only the LVEF and FMD were confirmed in multivariate Cox regression analysis. Conclusions: The LVEF and brachial artery FMD are independent prognostic determinants in patients with gynecological cancers.

Microtubules Increase Diastolic Stiffness in Failing Human Cardiomyocytes and Myocardium

BACKGROUND

Diastolic dysfunction is a prevalent and therapeutically intractable feature of heart failure (HF). Increasing ventricular compliance can improve diastolic performance, but the viscoelastic forces that resist diastolic filling and become elevated in human HF are poorly defined. Having recently identified posttranslationally detyrosinated microtubules as a source of viscoelasticity in cardiomyocytes, we sought to test whether microtubules contribute meaningful viscoelastic resistance to diastolic stretch in human myocardium.

METHODS

Experiments were conducted in isolated human cardiomyocytes and trabeculae. First, slow and rapid (diastolic) stretch was applied to intact cardiomyocytes from nonfailing and HF hearts and viscoelasticity was characterized after interventions targeting microtubules. Next, intact left ventricular trabeculae from HF patient hearts were incubated with colchicine or vehicle and subject to pre- and posttreatment mechanical testing, which consisted of a staircase protocol and rapid stretches from slack length to increasing strains.

RESULTS

Viscoelasticity was increased during diastolic stretch of HF cardiomyocytes compared with nonfailing counterparts. Reducing either microtubule density or detyrosination reduced myocyte stiffness, particularly at diastolic strain rates, indicating reduced viscous forces. In myocardial tissue, we found microtubule depolymerization reduced myocardial viscoelasticity, with an effect that decreased with increasing strain. Colchicine reduced viscoelasticity at strains below, but not above, 15%, with a 2-fold reduction in energy dissipation upon microtubule depolymerization. Post hoc subgroup analysis revealed that myocardium from patients with HF with reduced ejection fraction were more fibrotic and elastic than myocardium from patients with HF with preserved ejection fraction, which were relatively more viscous. Colchicine reduced viscoelasticity in both HF with preserved ejection fraction and HF with reduced ejection fraction myocardium.

CONCLUSIONS

Failing cardiomyocytes exhibit elevated viscosity and reducing microtubule density or detyrosination lowers viscoelastic resistance to diastolic stretch in human myocytes and myocardium. In failing myocardium, microtubules elevate stiffness over the typical working range of strains and strain rates, but exhibited diminishing effects with increasing length, consistent with an increasing contribution of the extracellular matrix or myofilament proteins at larger excursions. These studies indicate that a stabilized microtubule network provides a viscous impediment to diastolic stretch, particularly in HF.

Cardiac microtubules in health and heart disease

Cardiomyocytes are large (∼40,000 µm3), rod-shaped muscle cells that provide the working force behind each heartbeat. These highly structured cells are packed with dense cytoskeletal networks that can be divided into two groups—the contractile (i.e. sarcomeric) cytoskeleton that consists of filamentous actin-myosin arrays organized into myofibrils, and the non-sarcomeric cytoskeleton, which is composed of β- and γ-actin, microtubules, and intermediate filaments. Together, microtubules and intermediate filaments form a cross-linked scaffold, and these networks are responsible for the delivery of intracellular cargo, the transmission of mechanical signals, the shaping of membrane systems, and the organization of myofibrils and organelles. Microtubules are extensively altered as part of both adaptive and pathological cardiac remodeling, which has diverse ramifications for the structure and function of the cardiomyocyte. In heart failure, the proliferation and post-translational modification of the microtubule network is linked to a number of maladaptive processes, including the mechanical impediment of cardiomyocyte contraction and relaxation. This raises the possibility that reversing microtubule alterations could improve cardiac performance, yet therapeutic efforts will strongly benefit from a deeper understanding of basic microtubule biology in the heart. The aim of this review is to summarize the known physiological roles of the cardiomyocyte microtubule network, the consequences of its pathological remodeling, and to highlight the open and intriguing questions regarding cardiac microtubules.

Impact statement

Advancements in cell biological and biophysical approaches and super-resolution imaging have greatly broadened our view of tubulin biology over the last decade. In the heart, microtubules and microtubule-based transport help to organize and maintain key structures within the cardiomyocyte, including the sarcomere, intercalated disc, protein clearance machinery and transverse-tubule and sarcoplasmic reticulum membranes. It has become increasingly clear that post translational regulation of microtubules is a key determinant of their sub-cellular functionality. Alterations in microtubule network density, stability, and post-translational modifications are hallmarks of pathological cardiac remodeling, and modified microtubules can directly impede cardiomyocyte contractile function in various forms of heart disease. This review summarizes the functional roles and multi-leveled regulation of the cardiac microtubule cytoskeleton and highlights how refined experimental techniques are shedding mechanistic clarity on the regionally specified roles of microtubules in cardiac physiology and pathophysiology.

Microtubules Provide a Viscoelastic Resistance to Myocyte Motion

BACKGROUND

Microtubules (MTs) buckle and bear load during myocyte contraction, a behavior enhanced by post-translational detyrosination. This buckling suggests a spring-like resistance against myocyte shortening, which could store energy and aid myocyte relaxation. Despite this visual suggestion of elastic behavior, the precise mechanical contribution of the cardiac MT network remains to be defined.

METHODS

Here we experimentally and computationally probe the mechanical contribution of stable MTs and their influence on myocyte function. We use multiple approaches to interrogate viscoelasticity and cell shortening in primary murine myocytes in which either MTs are depolymerized or detyrosination is suppressed and use the results to inform a mathematical model of myocyte viscoelasticity.

RESULTS

MT ablation by colchicine concurrently enhances both the degree of shortening and speed of relaxation, a finding inconsistent with simple spring-like MT behavior and suggestive of a viscoelastic mechanism. Axial stretch and transverse indentation confirm that MTs increase myocyte viscoelasticity. Specifically, increasing the rate of strain amplifies the MT contribution to myocyte stiffness. Suppressing MT detyrosination with parthenolide or via overexpression of tubulin tyrosine ligase has mechanical consequences that closely resemble colchicine, suggesting that the mechanical impact of MTs relies on a detyrosination-dependent linkage with the myocyte cytoskeleton. Mathematical modeling affirms that alterations in cell shortening conferred by either MT destabilization or tyrosination can be attributed to internal changes in myocyte viscoelasticity.

CONCLUSIONS

The results suggest that the cardiac MT network regulates contractile amplitudes and kinetics by acting as a cytoskeletal shock-absorber, whereby MTs provide breakable cross-links between the sarcomeric and nonsarcomeric cytoskeleton that resist rapid length changes during both shortening and stretch.

The impact of paclitaxel and carboplatin chemotherapy on the autonomous nervous system of patients with ovarian cancer

Background

Paclitaxel-based regimens are frequently associated with the development of peripheral neuropathy. The autonomous nervous system (ANS) effects, however, of this chemotherapeutic agent remain unexplored.

Methods

We investigated a group of 31 female patients with ovarian cancer receiving treatment with paclitaxel and carboplatin, as well as a group of 16 healthy age- and gender-matched healthy volunteers. All study participants completed a questionnaire and were assessed neurophysiologically at three time points (baseline, 3–4 months and 6–8 months following the onset of chemotherapy). The evaluation of the ANS included assessment of the adrenergic cardiovascular function (orthostatic hypotension-OH), parasympathetic heart innervation (30/15 ratio) and sympathetic skin response (SSR).

Results

At the 3–4 months ANS assessment, 19.2 % of the patients had systolic OH and the same percentage had diastolic OH, but at the 6–8 months evaluation no patient had systolic OH and only 13.8 % had diastolic OH. The values of the 30/15 ratio were significantly reduced at both time points, whereas the SSR was not affected.

Conclusions

Combined paclitaxel and carboplatin chemotherapy is associated with significant effects on the parasympathetic heart innervation and occasionally with effects on the adrenergic cardiovascular reaction. The SSR remained unaffected. Physicians should be alert to the possibility of these treatment-emergent side effects, so as to monitor ANS parameters and introduce treatment modifications accordingly. Our findings however, should be validated in larger cohorts.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-016-0710-4) contains supplementary material, which is available to authorized users.