Lenvatinib and selpercatinib successfully treated RET fusion gene-positive papillary thyroid carcinoma cardiac metastases: a case report.

Background: Cardiac metastasis from thyroid cancer is rare and has an extremely poor prognosis. Although some patients who undergo heart surgery survive, the therapeutic effectiveness of systemic therapy is limited. Case Description: A 53-year-old woman with a history of papillary thyroid carcinoma (PTC) presented with cough and right chest discomfort. She underwent total thyroidectomy, followed by three rounds of radioactive iodine therapy, to treat pulmonary metastasis. Metastases to the lung, chest wall, liver, heart, and lymph nodes were observed on computed tomography. Core needle biopsy of the tumor in the right chest wall revealed the recurrence of PTC. Cardiac metastasis was discovered by echocardiography and cardiac magnetic resonance imaging, and blood test indicated a thyroglobulin level of 851 ng/mL. Based on the presence of cardiac metastasis and strong clinical symptoms, the condition was assumed to be fatal, and lenvatinib was started right away. Three weeks after starting lenvatinib, every metastatic lesion shrank. Once the ERC1-RET fusion gene was identified, we switched to selpercatinib therapy. Ten weeks after starting selpercatinib, every tumor shrank and blood thyroglobulin dropped to 68.1 ng/mL. Initial symptoms such as cough and right chest pain improved. Lenvatinib- and selpercatinib-related adverse effects can be managed with supportive care. Conclusions: To the best of our knowledge, this is the first case of successful systemic therapy for cardiac metastasis from PTC. Conventionally, cardiac surgery is the main treatment for cardiac metastasis, but now systemic therapy is also an important alternative.

Comparison of anti-inflammatory effects of rivaroxaban vs. dabigatran in patients with non-valvular atrial fibrillation (RIVAL-AF study): multicenter randomized study.

Some experimental studies have shown that direct oral anticoagulants (DOACs) have anti-inflammatory effects. However, the interval changes in inflammatory markers in patients with non-valvular atrial fibrillation (AF) who receive DOACs remain unknown. Between July 2013 and April 2014, a total of 187 AF patients randomly assigned to receive rivaroxaban (n = 91) or dabigatran (n = 96) were assessed for eligibility. The levels of the following inflammatory markers were serially evaluated: high-sensitivity C-reactive protein, pentraxin-3, interleukin (IL)-1ß, IL-6, IL-18, tumor necrosis factor-α, monocyte chemotactic protein-1, growth and differentiation factor-15, and soluble thrombomodulin (sTM). The aim in this study was to evaluate the anti-inflammatory effects of rivaroxaban and dabigatran in patients with AF, in addition to the impact of markers on bleeding events. Finally, 117 patients (rivaroxaban: n = 55, dabigatran: n = 62) were included in the analysis at 12 months. Although the interval changes in sTM levels tended to be greater in the dabigatran group [0.3 (0-0.7) vs. 0.5 (0-1.0) FU/ml, p = 0.061], there were no significant differences in the interval changes in any inflammatory marker between 2 groups. There were no significant differences in bleeding events between 2 groups. The interval changes in sTM levels were significantly greater in patients with bleeding compared with those without [0.8 (0.5-1.3) vs. 0.4 (- 0.1-0.8) FU/ml, p = 0.017]. There were no significant differences in the interval changes in any inflammatory marker between rivaroxaban and dabigatran treatments in patients with AF. The increased levels of sTM after DOACs treatment might be related to bleeding events.

A case of heparin-induced thrombocytopenia with subacute stent thrombosis, multiple cerebral infarction, and acute limb ischemia.

Heparin-induced thrombocytopenia (HIT) is an adverse immune-mediated drug reaction that is associated with thromboembolic complications. We report the case of an 82-year-old man with unstable angina pectoris who suffered from recurrent arterial thromboembolism due to HIT. Coronary angiography (CAG) was performed while we administered unfractionated heparin bolus. CAG showed triple-vessel disease without left main coronary artery. We performed elective percutaneous coronary angioplasty (PCI) to the left anterior descending coronary artery (LAD). The sudden thrombus formation in the LAD occurred during the procedure. We suspected HIT and administered argatroban. We deployed four everolimus-eluting stents in the LAD and intra-aortic balloon pumping (IABP) support was started. The platelet counts were rapidly reduced almost 50% next day after PCI and IgG-specific anti-PF4/heparin antibodies were elevated. Multiple cerebral infarctions were detected by magnetic resonance imaging after the PCI. The patient received the continuous argatroban administration and IABP support for 4 days. Subacute stent thrombosis occurred after quitting argatroban. We performed thrombus aspiration and fibrinolytic treatment. Finally we re-inserted IABP and stabilized the hemodynamic state. Right popliteal arterial thromboembolism occurred after emergency PCI. Argatroban is essential and following oral anticoagulant therapy is necessary to prevent thromboembolic complications. .

Coupling of ß1-adrenergic receptor to type 5 adenylyl cyclase and its physiological relevance in cardiac myocytes.

Myocardial ß-adrenergic receptor (ß-AR) ß1- and ß2-subtypes are highly homologous, but play opposite roles in cardiac apoptosis and heart failure, as do cardiac adenylyl cyclase (AC) subtypes 5 (AC5) and 6 (AC6): ß1-AR and AC5 promote cardiac remodeling, while ß2-AR and AC6 activate cell survival pathways. However, the mechanisms involved remain poorly understood. We hypothesized that AC5 is coupled preferentially to ß1-AR rather than ß2-AR, and we examined this idea by means of pharmacological and genetic approaches. We found that selective inhibition of AC5 with 2'5'-dideoxyadenosine significantly suppressed cAMP accumulation and cardiac apoptosis induced by selective ß1-AR stimulation, but had no effect on cAMP accumulation and cardiac apoptosis in response to selective ß2-AR stimulation. The results of selective stimulation of ß1-AR and ß2-AR in neonatal cardiac myocytes prepared from wild-type and AC5-knockout mice were also consistent with the idea that ß1-AR selectively couples with AC5. We believe these results are helpful for understanding the mechanisms underlying the different roles of AR subtypes in healthy and diseased hearts.

Epac1-dependent phospholamban phosphorylation mediates the cardiac response to stresses.

PKA phosphorylates multiple molecules involved in calcium (Ca2+) handling in cardiac myocytes and is considered to be the predominant regulator of ß-adrenergic receptor-mediated enhancement of cardiac contractility; however, recent identification of exchange protein activated by cAMP (EPAC), which is independently activated by cAMP, has challenged this paradigm. Mice lacking Epac1 (Epac1 KO) exhibited decreased cardiac contractility with reduced phospholamban (PLN) phosphorylation at serine-16, the major PKA-mediated phosphorylation site. In Epac1 KO mice, intracellular Ca2+ storage and the magnitude of Ca2+ movement were decreased; however, PKA expression remained unchanged, and activation of PKA with isoproterenol improved cardiac contractility. In contrast, direct activation of EPAC in cardiomyocytes led to increased PLN phosphorylation at serine-16, which was dependent on PLC and PKCε. Importantly, Epac1 deletion protected the heart from various stresses, while Epac2 deletion was not protective. Compared with WT mice, aortic banding induced a similar degree of cardiac hypertrophy in Epac1 KO; however, lack of Epac1 prevented subsequent cardiac dysfunction as a result of decreased cardiac myocyte apoptosis and fibrosis. Similarly, Epac1 KO animals showed resistance to isoproterenol- and aging-induced cardiomyopathy and attenuation of arrhythmogenic activity. These data support Epac1 as an important regulator of PKA-independent PLN phosphorylation and indicate that Epac1 regulates cardiac responsiveness to various stresses.

Pharmacological stimulation of type 5 adenylyl cyclase stabilizes heart rate under both microgravity and hypergravity induced by parabolic flight.

We previously demonstrated that type 5 adenylyl cyclase (AC5) functions in autonomic regulation in the heart. Based on that work, we hypothesized that pharmacological modulation of AC5 activity could regulate the autonomic control of the heart rate under micro- and hypergravity. To test this hypothesis, we selected the approach of activating AC5 activity in mice with a selective AC5 activator (NKH477) or inhibitor (vidarabine) and examining heart rate variability during parabolic flight. The standard deviation of normal R-R intervals, a marker of total autonomic variability, was significantly greater under micro- and hypergravity in the vidarabine group, while there were no significant changes in the NKH477 group, suggesting that autonomic regulation was unstable in the vidarabine group. The ratio of low frequency and high frequency (HF) in heart rate variability analysis, a marker of sympathetic activity, became significantly decreased under micro- and hypergravity in the NKH477 group, while there was no such decrease in the vidarabine group. Normalized HF, a marker of parasympathetic activity, became significantly greater under micro- and hypergravity in the NKH477 group. In contrast, there was no such increase in the vidarabine group. This study is the first to indicate that pharmacological modulation of AC5 activity under micro- and hypergravity could be useful to regulate the autonomic control of the heart rate.

Type 5 adenylyl cyclase plays a major role in stabilizing heart rate in response to microgravity induced by parabolic flight.

It is well known that autonomic nervous activity is altered under microgravity, leading to disturbed regulation of cardiac function, such as heart rate. Autonomic regulation of the heart is mostly determined by beta-adrenergic receptors/cAMP signal, which is produced by adenylyl cyclase, in cardiac myocytes. To examine a hypothesis that a major cardiac isoform, type 5 adenylyl cyclase (AC5), plays an important role in regulating heart rate during parabolic flights, we used transgenic mouse models with either disrupted (AC5KO) or overexpressed AC5 in the heart (AC5TG) and analyzed heart rate variability. Heart rate had a tendency to decrease gradually in later phases within one parabola in each genotype group, but the magnitude of decrease was smaller in AC5KO than that in the other groups. The inverse of heart rate, i.e., the R-R interval, was much more variable in AC5KO and less variable in AC5TG than that in wild-type controls. The standard deviation of normal R-R intervals, a marker of total autonomic variability, was significantly greater in microgravity phase in each genotype group, but the magnitude of increase was much greater in AC5KO than that in the other groups, suggesting that heart rate regulation became unstable in the absence of AC5. In all, AC5 plays a major role in stabilizing heat rate under microgravity.

Dopamine induces apoptosis in young, but not in neonatal, neurons via Ca2+-dependent signal.

Dopamine signaling plays a major role in regulation of neuronal apoptosis. During the postnatal period, dopamine signaling is known to be dramatically changed in the striatum. However, because it is difficult to culture neurons after birth, little is known about developmental changes in dopamine-mediated apoptosis. To examine such changes, we established the method of primary culture of striatal neurons from 2- to 3-wk-old (young) mice. Dopamine, via D(1)-like receptors, induced apoptosis in young, but not neonatal, striatal neurons, suggesting that the effect of dopamine on apoptosis changed with development. In contrast, although isoproterenol (Iso), a beta-adrenergic receptor agonist, increased cAMP production to a greater degree than dopamine, Iso did not increase apoptosis in striatal neurons from young and neonatal mice, suggesting a minor role of cAMP in dopamine-mediated apoptosis. Next, we examined the effect of dopamine on Ca(2+) signaling. Dopamine, but not Iso, markedly increased intracellular Ca(2+) in striatal neurons from young mice, and Ca(2+)-chelating agents abolished dopamine-induced apoptosis, suggesting that Ca(2+) played a major role in the dopamine-mediated apoptosis pathway. In contrast, dopamine failed to increase intracellular Ca(2+) in neonatal neurons, and the expression of PLC, which can increase intracellular Ca(2+) via D(1)-like receptor activation, was significantly greater in young than in neonatal striatal neurons. These data suggest that the developmental change in dopamine-mediated Ca(2+) signaling was responsible for differences between young and neonatal striatum in induction of apoptosis. Furthermore, the culture of young striatal neurons is feasible and may provide a new tool for developmental studies.

Serial alterations of beta-adrenergic signaling in dilated cardiomyopathic hamsters: possible role of myocardial oxidative stress.

BACKGROUND: The relationship between enhanced myocardial oxidative stress and impaired beta-adrenergic signaling remains to be characterized during the development of dilated cardiomyopathy. METHODS AND RESULTS: Alterations in myocardial oxidative stress and beta-adrenergic signaling, as well as left ventricular (LV) functional and structural changes, were evaluated during the development of cardiomyopathy in TO-2 hamsters; F1B hamsters served as controls. LV dysfunction was first apparent at 8 weeks of age and deteriorated thereafter in the TO-2 hamsters. At 32 weeks, the animals exhibited heart failure with an increased plasma norepinephrine concentration. Cardiac myolysis, as demonstrated by elevated plasma concentration of cardiac troponin T, peaked at 8 weeks. The glutathione redox ratio revealed increased oxidative stress in the LV myocardium in TO-2 hamsters even at 4 weeks and became manifest after 8 weeks. The hearts of TO-2 hamsters had significantly reduced superoxide dismutase activity from 8 weeks onward compared with control hamsters. However, glutathione peroxidase activity was unchanged at any time point. The LV functional response to isoproterenol was markedly reduced at 8 weeks, without any apparent changes in the amount of beta-adrenergic signaling molecules, and it deteriorated thereafter. Adenylyl cyclase activity was significantly decreased, despite increased amounts of both G(s) alpha mRNA and protein, in the LV myocardium at 18 weeks. CONCLUSIONS: Myocardial oxidative stress is actually enhanced in the initial development of LV dysfunction. Both activation of myocardial oxidative stress and impairment of beta-adrenergic signaling become prominent at the stage of severe LV dysfunction. Myocardial oxidative stress may be involved in the development of beta-adrenergic desensitization.

Insulin resistance in skeletal muscles of caveolin-3-null mice.

Type 2 diabetes is preceded by the development of insulin resistance, in which the action of insulin is impaired, largely in skeletal muscles. Caveolin-3 (Cav3) is a muscle-specific subtype of caveolin, an example of a scaffolding protein found within membranes. Cav is also known as growth signal inhibitor, although it was recently demonstrated that the genetic disruption of Cav3 did not augment growth in mice. We found, however, that the lack of Cav3 led to the development of insulin resistance, as exemplified by decreased glucose uptake in skeletal muscles, impaired glucose tolerance test performance, and increases in serum lipids. Such impairments were markedly augmented in the presence of streptozotocin, a pancreatic beta cell toxin, suggesting that the mice were susceptible to severe diabetes in the presence of an additional risk factor. Insulin-stimulated activation of insulin receptors and downstream molecules, such as IRS-1 and Akt, was attenuated in the skeletal muscles of Cav3 null mice, but not in the liver, without affecting protein expression or subcellular localization. Genetic transfer of Cav3 by needle injection restored insulin signaling in skeletal muscles. Our findings suggest that Cav3 is an enhancer of insulin signaling in skeletal muscles but does not act as a scaffolding molecule for insulin receptors.

Direct inhibition of type 5 adenylyl cyclase prevents myocardial apoptosis without functional deterioration.

Adenylyl cyclase, a major target enzyme of beta-adrenergic receptor signals, is potently and directly inhibited by P-site inhibitors, classic inhibitors of this enzyme, when the enzyme catalytic activity is high. Unlike beta-adrenergic receptor antagonists, this is a non- or uncompetitive inhibition with respect to ATP. We have examined whether we can utilize this enzymatic property to regulate the effects of beta-adrenergic receptor stimulation differentially. After screening multiple new and classic compounds, we found that some compounds, including 1R,4R-3-(6-aminopurin-9-yl)-cyclopentanecarboxylic acid hydroxyamide, potently inhibited type 5 adenylyl cyclase, the major cardiac isoform, but not other isoforms. In normal mouse cardiac myocytes, contraction induced by low beta-adrenergic receptor stimulation was poorly inhibited with this compound, but the induction of cardiac myocyte apoptosis by high beta-adrenergic receptor stimulation was effectively prevented by type 5 adenylyl cyclase inhibitors. In contrast, when cardiac myocytes from type 5 adenylyl cyclase knock-out mice were examined, beta-adrenergic stimulation poorly induced apoptosis. Our data suggest that the inhibition of beta-adrenergic signaling at the level of the type 5 adenylyl cyclase isoform by P-site inhibitors may serve as an effective method to prevent cardiac myocyte apoptosis induced by excessive beta-adrenergic stimulation without deleterious effect on cardiac myocyte contraction.

Disruption of type 5 adenylyl cyclase negates the developmental increase in Galphaolf expression in the striatum.

The two stimulatory G protein alpha subunits, Galphas and Galphaolf, activate adenylyl cyclase in a similar way. We examined whether type 5 adenylyl cyclase knockout, the major striatal isoform, can differentially and/or developmentally change the expression of these G proteins in the striatum. Galphas and Galphaolf expressions at birth were unaffected in knockouts, which, however, demonstrated a blunted developmental increase in Galphaolf, but not Galphas. Adenylyl cyclase activity was unaffected at birth, but subsequently became lower in knockouts. These findings suggest that type 5 adenylyl cyclase does not contribute to striatal cAMP signaling at birth. However, it may play an important role in developmental changes in the expression of Galphaolf, but not Galphas.

Isoform-specific regulation of adenylyl cyclase: a potential target in future pharmacotherapy.

Adenylyl cyclase (AC) is a target enzyme of multiple G-protein-coupled receptors (GPCRs). In the past decade, the cloning, structure and biochemical properties of nine AC isoforms were reported, and each isoform of AC shows distinct patterns of tissue distribution and biochemical/pharmacological properties. In addition to the conventional regulators of this enzyme, such as calmodulin (CaM) or PKC, novel regulators, for example, caveolin, have been identified. Most importantly, these regulators work on AC in an isoform dependent manner. Recent studies have demonstrated that certain classic AC inhibitors, i.e., P-site inhibitors, show an isoform-dependent inhibition of AC. The side chain modifications of forskolin, a diterpene extract from Coleus forskolii, markedly enhance its isoform selectivity. When taken together, these findings suggest that it is feasible to develop new pharmacotherapeutic agents that target AC isoforms to regulate various neurohormonal signals in a highly tissue-/organ-specific manner.

Polymorphism of the type 6 adenylyl cyclase gene and cardiac hypertrophy.

We investigated whether polymorphism of the type 6 adenylyl cyclase gene influences the occurrence of left ventricular hypertrophy in a Japanese population. Type 6 adenylyl cyclase is a major cardiac adenylyl cyclase isoform and plays an important role in regulating cardiac function. We examined the type 6 adenylyl cyclase gene for single nucleotide polymorphism by heteroduplex analysis and found a mutation (T11215A) in intron 17. We genotyped the single nucleotide polymorphism (TT/TA/AA groups) by the mutagenically separated polymerase chain reaction method in 2068 subjects who underwent health screening for cardiovascular disease. Genetic variation was in the Hardy-Weinberg equilibrium. We found no significant association between the frequency of left ventricular hypertrophy and any of the genotype groups. In the TT and the TA genotype group, however, left ventricular hypertrophy was associated with increased blood pressure, while no association with increased blood pressure was found in the AA genotype group. It was concluded that the AA group may be at risk of developing left ventricular hypertrophy independent of increased blood pressure.