Clinical Perspectives of Parkinson's Disease for Ophthalmologists, Otorhinolaryngologists, Cardiologists, Dentists, Gastroenterologists, Urologists, Physiatrists, and Psychiatrists

Emerging perspectives on precision therapy for Parkinson's disease: multidimensional evidence leading to a new breakthrough in personalized medicine

PD is a prevalent and progressive neurodegenerative disorder characterized by both motor and non-motor symptoms. Genes play a significant role in the onset and progression of the disease. While the complexity and pleiotropy of gene expression networks have posed challenges for gene-targeted therapies, numerous pathways of gene variant expression show promise as therapeutic targets in preclinical studies, with some already in clinical trials. With the recognition of the numerous genes and complex pathways that can influence PD, it may be possible to take a novel approach to choose a treatment for the condition. This approach would be based on the symptoms, genomics, and underlying mechanisms of the disease. We discuss the utilization of emerging genetic and pathological knowledge of PD patients to categorize the disease into subgroups. Our long-term objective is to generate new insights for the therapeutic approach to the disease, aiming to delay and treat it more effectively, and ultimately reduce the burden on individuals and society.

A liquid crystal in situ gel based on rotigotine for the treatment of Parkinson's disease

One of the most common neurodegenerative illnesses is Parkinson's disease (PD). Rotigotine (RTG) is a dopamine agonist that exerts anti-Parkinsonian effects through dopamine receptor agonism to improve motor symptoms and overall performance in PD patients. In this study, an in situ liquid crystal gel called rotigotine-gel (RTG-gel) was developed using soya phosphatidyl choline (SPC) and glycerol dioleate (GDO) to provide long-acting slow-release benefits of rotigotine while minimizing side effects. This study prepared the RTG-gel precursor solution using SPC, GDO, and ethanol (in the ratio of 54:36:10, w/w/w). The internal structures of the gel were confirmed by crossed-polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC). The rheological properties of the RTG-gel precursor solution indicate a favorable combination of low viscosity and excellent flowability. The gel that produced during water absorption was also highly viscous and structurally stable, which helped to maintain the drug delayed release at the injection site. In vitro release assays showed that the in vitro release of RTG-gel followed Ritger-Peppas. The RTG-gel precursor solution was administered by subcutaneous injection, and the results of in vivo pharmacokinetic tests in SD rats showed that the plasma elimination half-life (t1/2) was 59.28 ± 16.08 h; the time to peak blood concentration (Tmax) was 12.00 ± 10.32 h, and the peak concentration (Cmax) was 29.9 ± 10.10 ng/mL. The blood concentration remained above 0.1 ng/mL for 20 days after administration and was still detectable after 31 days of administration, and the bioavailability of RTG can reach 72.59%. The results of in vitro solvent exchange tests showed that the RTG-gel precursor solution undergoes rapid exchange upon contact with PBS, and the diffusion of ethanol can reach 48.1% within 60 min and 80% within 8 h. The results of cytotoxicity test showed 89.27 ± 4.32% cell survival after administration of the drug using RTG-gel. The results of tissue extraction at the administration site showed that healing of the injection site without redness and hemorrhage could be observed after 14 days of injection. The results of tissue section of the administered site showed that the inflammatory cells decreased and granulation tissue appeared after 14 days of administration, and there was basically no inflammatory cell infiltration after 35 days of administration, and the inflammatory reaction was basically eliminated. It shows that RTG-gel has some irritation to the injection site, but it can be recovered by itself in the later stage, and it has good biocompatibility. In summary, RTG-gel might be a potential RTG extended-release formulation for treating PD.

Dysphagia Requiring Medical Attention in Parkinson's Disease: A Korean Population-Based Study

BACKGROUND

Patients with Parkinson's disease (PD) experience both motor and non-motor symptoms, including dysphagia. Although PD is closely associated with dysphagia, the prevalence or risk of dysphagia in PD is unclear, especially in Asian countries.

METHODS

The prevalence of PD and dysphagia with PD in the general population was analyzed using the Korean National Health Insurance Service (NHIS) database. The prevalence per 100,000 persons of PD and dysphagia with PD from 2006 to 2015 was analyzed in the general population aged ≥ 40 years. Patients newly diagnosed with PD between 2010 and 2015 were compared with those without PD.

RESULTS

The prevalence of PD and dysphagia in patients with PD increased continuously during the study period and was highest in the ninth decade of life. The percentage of patients with dysphagia in patients with PD increased with age. Patients with PD showed an adjusted hazard ratio of 3.132 (2.955-3.320) for dysphagia compared to those without PD.

CONCLUSION

This nationwide study showed increasing trends in the prevalence of PD and dysphagia among patients with PD in Korea between 2006 and 2015. The risk of dysphagia was three times higher in patients with PD than that in those without PD, highlighting the importance of providing particular attention.

Premotor, nonmotor and motor symptoms of Parkinson's Disease: A new clinical state of the art

Parkinson's Disease (PD) is a neurodegenerative disorder that affects dopaminergic neurons in the mesencephalic substantia nigra, causing a progressive clinical course characterized by pre-motor, non-motor and motor symptoms, which negatively impact the quality of life of patients and cause high health care costs. Therefore, the present study aims to discuss the clinical manifestations of PD and to make a correlation with the gut-brain (GB) axis, approaching epidemiology and therapeutic perspectives, to better understand its clinical progression and identify symptoms early. A literature review was performed regarding the association between clinical progression, the gut-brain axis, epidemiology, and therapeutic perspectives, in addition to detailing pre-motor, non-motor symptoms (neuropsychiatric, cognitive, autonomic, sleep disorders, sensory abnormalities) and cardinal motor symptoms. Therefore, this article addresses a topic of extreme relevance, since the previously mentioned clinical manifestations (pre-motor and non-motor) can often act as prodromal markers for the early diagnosis of PD and may precede it by up to 20 years.

Growing role of S100B protein as a putative therapeutic target for neurological- and nonneurological-disorders

S100B is a calcium-binding protein mainly expressed by astrocytes, but also localized in other definite neural and extra-neural cell types. While its presence in biological fluids is widely recognized as a reliable biomarker of active injury, growing evidence now indicates that high levels of S100B are suggestive of pathogenic processes in different neural, but also extra-neural, disorders. Indeed, modulation of S100B levels correlates with the occurrence of clinical and/or toxic parameters in experimental models of diseases such as Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, muscular dystrophy, multiple sclerosis, acute neural injury, inflammatory bowel disease, uveal and retinal disorders, obesity, diabetes and cancer, thus directly linking the levels of S100B to pathogenic mechanisms. In general, deletion/inactivation of the protein causes the improvement of the disease, whereas its over-expression/administration induces a worse clinical presentation. This scenario reasonably proposes S100B as a common therapeutic target for several different disorders, also offering new clues to individuate possible unexpected connections among these diseases.

Temporal Vestibular Deficits in synaptojanin 1 (synj1) Mutants

The lipid phosphatase synaptojanin 1 (synj1) is required for the disassembly of clathrin coats on endocytic compartments. In neurons such activity is necessary for the recycling of endocytosed membrane into synaptic vesicles. Mutations in zebrafish synj1 have been shown to disrupt the activity of ribbon synapses in sensory hair cells. After prolonged mechanical stimulation of hair cells, both phase locking of afferent nerve activity and the recovery of spontaneous release of synaptic vesicles are diminished in synj1 mutants. Presumably as a behavioral consequence of these synaptic deficits, synj1 mutants are unable to maintain an upright posture. To probe vestibular function with respect to postural control in synj1 mutants, we developed a method for assessing the vestibulospinal reflex (VSR) in larvae. We elicited the VSR by rotating the head and recorded tail movements. As expected, the VSR is completely absent in pcdh15a and lhfpl5a mutants that lack inner ear function. Conversely, lhfpl5b mutants, which have a selective loss of function of the lateral line organ, have normal VSRs, suggesting that the hair cells of this organ do not contribute to this reflex. In contrast to mechanotransduction mutants, the synj1 mutant produces normal tail movements during the initial cycles of rotation of the head. Both the amplitude and temporal aspects of the response are unchanged. However, after several rotations, the VSR in synj1 mutants was strongly diminished or absent. Mutant synj1 larvae are able to recover, but the time required for the reappearance of the VSR after prolonged stimulation is dramatically increased in synj1 mutants. Collectively, the data demonstrate a behavioral correlate of the synaptic defects caused by the loss of synj1 function. Our results suggest that defects in synaptic vesicle recycling give rise to fatigue of ribbons synapses and possibly other synapses of the VS circuit, leading to the loss of postural control.