Heart valve disease associated with treatment with ergot-derived dopamine agonists: a clinical and echocardiographic study of patients with Parkinson's disease

Lipid-based nanodelivery approaches for dopamine-replacement therapies in Parkinson's disease: From preclinical to translational studies

The incidence of Parkinson's disease (PD), the second most common neurodegenerative disorder, has increased exponentially as the global population continues to age. Although the etiological factors contributing to PD remain uncertain, its average incidence rate is reported to be 1% of the global population older than 60 years. PD is primarily characterized by the progressive loss of dopaminergic (DAergic) neurons and/or associated neuronal networks and the subsequent depletion of dopamine (DA) levels in the brain. Thus, DA or levodopa (l-dopa), a precursor of DA, represent cardinal targets for both idiopathic and symptomatic PD therapeutics. While several therapeutic strategies have been investigated over the past decade for their abilities to curb the progression of PD, an effective cure for PD is currently unavailable. Even DA replacement therapy, an effective PD therapeutic strategy that provides an exogenous supply of DA or l-dopa, has been hindered by severe challenges, such as a poor capacity to bypass the blood-brain barrier and inadequate bioavailability. Nevertheless, with recent advances in nanotechnology, several drug delivery systems have been developed to bypass the barriers associated with central nervous system therapeutics. In here, we sought to describe the adapted lipid-based nanodrug delivery systems used in the field of PD therapeutics and their recent advances, with a particular focus placed on DA replacement therapies. This work initially explores the background of PD; offers descriptions of the most recent molecular targets; currently available clinical medications/limitations; an overview of several lipid-based PD nanotherapeutics, functionalized nanoparticles, and technical aspects in brain delivery; and, finally, presents future perspectives to enhance the use of nanotherapeutics in PD treatment.

Evaluation of the effect of non-ergot dopamine agonists on left ventricular systolic function with speckle tracking echocardiography

Objective:

Parkinson’s disease (PD) is a neurological disorder, and ergot dopamine agonists (DAs) are no longer usually preferred in the treatment due to the increased risk of valvular heart disease. Some recent studies have shown that commonly used non-ergot DA also increases the risk of heart failure. On the other hand, there are studies showing conflicting data about this relationship. The aim of the present study was to investigate the cardiac effects of non-ergot DAs in patients with PD using echocardiography.

Methods:

Conventional echocardiography and two-dimensional (2D) speckle tracking strain echocardiography were performed to determine the possible systolic dysfunction prior to the development of apparent systolic heart failure. Ninety-one (55 male, 64±10 years) patients with PD were included in the study. Furthermore, 25 subjects with newly diagnosed PD and using no drug were enrolled as the control group. All patients were divided into groups according to their medication. Patients using levodopa were classified as Group 1 (36), levodopa+pramipexole as Group 2 (27), and levodopa+ropinirole as Group 3 (28).

Results:

Left ventricle dysfunction with non-ergot DA use in patients with PD was not established with conventional echocardiographic evaluation. For 2D strain analysis, global longitudinal strain values were obtained as −18.5%, −18.5%, and −18.9% in the groups, respectively. Strain and strain rate values of the left ventricle were not different between the groups (p=0.816 and p=0.881, respectively).

Conclusion:

There was no significant relationship between left ventricular dysfunction and use of non-ergot DA in patients with PD. Similar results were obtained in strain analysis showing left ventricular subclinical dysfunction. Our study appears to confirm the safety of non-ergot DA in the point of heart failure risk. To our knowledge, this is the first study to evaluate the effect of this group of drugs on subclinical left ventricular systolic function.

Evaluation of cardiovascular risk in patients with Parkinson disease under levodopa treatment

BACKGROUND

Levodopa is the indispensable choice of medial therapy in patients with Parkinson disease (PD). Since L-dopa treatment was shown to increase serum homocysteine levels, a well-known risk factor for cardiovascular disorders, the patients with PD under L-dopa treatment will be at increased risk for future cardiovascular events. The objective of this study is to evaluate cardiovascular risk in patients with PD under levodopa treatment.

METHODS

The study population consisted of 65 patients with idiopathic PD under L-dopa treatment. The control group included 32 age and gender matched individuals who had no cognitive decline. Echocardiographic measurements, serum homocysteine levels and elastic parameters of the aorta were compared between the patients with PD and controls.

RESULTS

As an expected feature of L-dopa therapy, the Parkinson group had significantly higher homocystein levels (15.1 ± 3.9 µmol/L vs. 11.5 ± 3.2 µmol/L, P = 0.02). Aortic distensibility was significantly lower in the patients with PD when compared to controls (4.8 ± 1.5 dyn/cm(2) vs. 6.2 ± 1.9 dyn/cm(2), P = 0.016). Additionally, the patients with PD had higher aortic strain and aortic stiffness index (13.4% ± 6.4% vs. 7.4% ± 3.6%, P < 0.001 and 7.3 ± 1.5 vs. 4.9 ± 1.9, P < 0.001 respectively). Furthermore, serum homocysteine levels were found to be positively correlated with aortic stiffness index and there was a negative correlation between aortic distensibility and levels of serum homocysteine (r = 0.674, P < 0.001; r = -0.602, P < 0.001, respectively).

CONCLUSIONS

The patients with PD under L-dopa treatment have increased aortic stiffness and impaired diastolic function compared to healthy individuals. Elevated serum homocysteine levels may be a possible pathophysiological mechanism.

New avenues in the medical treatment of Cushing's disease: corticotroph tumor targeted therapy

Cushing's disease (CD) is a condition of chronic hypercortisolism caused by an adrenocorticotropic hormone-secreting pituitary adenoma. First-line transsphenoidal surgery is not always curative and disease sometimes recurs. Radiotherapy often requires months or years to be effective, and is also not curative in many cases. Consequently, effective medical therapies for patients with CD are needed. Corticotroph adenomas frequently express both dopamine (D2) and somatostatin receptors (predominantly sstr5). Pasireotide, a somatostatin analog with high sstr5 binding affinity, has shown urinary free cortisol (UFC) reductions in most patients with CD in a large phase 3 trial, with UFC normalization and tumor shrinkage in a subset of patients. Adverse events were similar to other somatostatin analogs, with the exception of the degree and severity of hyperglycemia. Two small trials (one prospective and one retrospective) have suggested that cabergoline, a D2 receptor agonist, could be effective in normalizing UFC, but current long-term data results are conflicting. Combination treatment with pasireotide plus cabergoline and the adrenal steroidogenesis inhibitor ketoconazole has been successful, but further investigation in larger trials is necessary. Retinoic acid also showed interesting results in a recent very small prospective study. Glucocorticoid receptor blockade with mifepristone has recently demonstrated improvement in signs and symptoms of Cushing's and glycemic control; however, this modality does not address the etiology of the disease and has inherent adverse events related to its mechanism of action. Pituitary-targeted medical therapies will soon play a more prominent role in treating CD, and may potentially become first-line medical therapy when surgery fails or is contraindicated.