α-synuclein biomarker assays: bridging research and patient care.

The discovery that α-synuclein can be detected in peripheral tissues of patients with Parkinson's disease and other synucleinopathies spurred the development of biomarker assays, including the α-synuclein seed amplification assay for CSF and immunofluorescence detection of dermal phosphorylated-α-synuclein. These tools aim to identify pathological α-synuclein changes, even at the early stages of disease, with the goal of eventually enabling differentiation of Parkinson's disease from other neurodegenerative disorders, including tauopathies. α-synuclein biomarkers add a biological component to the traditional clinical diagnosis of Parkinson's disease, with potential for development of complementary clinical and pathobiological frameworks for Parkinson's disease and related movement disorders.

Tau biomarkers for neurodegenerative diseases: Current state and perspectives.

Neurodegenerative diseases, particularly tauopathies, pose significant global health challenges, especially in aging populations. Tauopathies are characterized by progressive neuronal damage and intracellular deposits of hyperphosphorylated tau. Early and accurate diagnosis is hindered by overlapping clinical features and reliance on post-mortem analyses, emphasizing the need for reliable in vivo biomarkers to improve early diagnosis and management.

Age- and sex-related variations in extracellular vesicle profiling for the assessment of cardiovascular risk: the EVaging index.

Extracellular vesicles (EVs) offer valuable diagnostic and prognostic insights for cardiovascular (CV) diseases, but the influence of age-related chronic inflammation ("inflammaging") and sex differences on EV profiles linked to CV risk remains unclear. This study aimed to use EV profiling to predict age and stratify patients by CV risk. We developed an EVaging index by analyzing surface antigen profiles of serum EVs from 625 participants, aged 20 to 94 years, across varying CV risk groups.

Skin Tau Quantification as a Novel Biomarker in Huntington's Disease.

Background: Emerging research implicates tau protein dysregulation in the pathophysiology of Huntington's disease.

Objective: This study investigated skin tau quantification as a potential biomarker for Huntington's disease and its correlation with disease burden outcomes.

Methods: In this cross-sectional study, we measured skin tau levels using enzyme-linked immunosorbent assay in 23 Huntington's disease mutations carriers and eight control subjects, examining group discrimination, correlations with genetic markers, clinical assessments, and neuroimaging data.

Tau seeding activity in skin biopsy differentiates tauopathies from synucleinopathies.

Most neurodegenerative diseases lack definitive diagnostic tests, and the identification of easily accessible and reliable biomarkers remains a critical unmet need. Since tau protein is highly expressed in skin of tauopathies patients, we aimed to exploit the ultrasensitive seeding activity assay (SAA) to assess tau seeding activity in skin of patients with tauopathies. In this multicentric, case-control study, patients with tauopathies and synucleinopathies were consecutively recruited and sex-matched to healthy controls (HC).

Amyloid detection and typing yield of skin biopsy in systemic amyloidosis and polyneuropathy.

Objective: Disease-modifying therapies are available for amyloidosis but are ineffective if end-organ damage is severe. As small fiber neuropathy is an early and common feature of amyloidosis, we assessed detection and typing yield of skin biopsy for amyloid in patients with confirmed systemic amyloidosis and neuropathic symptoms.

Methods: In this case-control study, patients with transthyretin and light chain amyloidosis (ATTRv, ATTRwt, and AL) were consecutively recruited.

Dorsal Root Ganglion Stimulation in Chronic Painful Polyneuropathy: A Potential Modulator for Small Nerve Fiber Regeneration.

Objectives: Neuromodulatory treatments like spinal cord stimulation and dorsal root ganglion stimulation (DRGS) have emerged as effective treatments to relieve pain in painful polyneuropathy. Animal studies have demonstrated that neurostimulation can enhance nerve regeneration. This study aimed to investigate if DRGS may impact intraepidermal nerve fiber regeneration and sensory nerve function.

Supervised and unsupervised learning to define the cardiovascular risk of patients according to an extracellular vesicle molecular signature.

Cardiovascular (CV) disease represents the most common cause of death in developed countries. Risk assessment is highly relevant to intervene at individual level and implement prevention strategies. Circulating extracellular vesicles (EVs) are involved in the development and progression of CV diseases and are considered promising biomarkers.

Alpha-synuclein oligomers and small nerve fiber pathology in skin are potential biomarkers of Parkinson's disease.

The proximity ligation assay (PLA) is a specific and sensitive technique for the detection of αSyn oligomers (αSyn-PLA), early and toxic species implicated in the pathogenesis of PD. We aimed to evaluate by skin biopsy the diagnostic and prognostic capacity of αSyn-PLA and small nerve fiber reduction in PD in a longitudinal study. αSyn-PLA was performed in the ankle and cervical skin biopsies of PD (n = 30), atypical parkinsonisms (AP, n = 23) including multiple system atrophy (MSA, n = 12) and tauopathies (AP-Tau, n = 11), and healthy controls (HC, n = 22).

Extracellular Vesicles as Promising Carriers in Drug Delivery: Considerations from a Cell Biologist's Perspective.

The use of extracellular vesicles as cell-free therapy is a promising approach currently investigated in several disease models. The intrinsic capacity of extracellular vesicles to encapsulate macromolecules within their lipid bilayer membrane-bound lumen is a characteristic exploited in drug delivery to transport active pharmaceutical ingredients. Besides their role as biological nanocarriers, extracellular vesicles have a specific tropism towards target cells, which is a key aspect in precision medicine.

Profiling Inflammatory Extracellular Vesicles in Plasma and Cerebrospinal Fluid: An Optimized Diagnostic Model for Parkinson's Disease.

Extracellular vesicles (EVs) play a central role in intercellular communication, which is relevant for inflammatory and immune processes implicated in neurodegenerative disorders, such as Parkinson's Disease (PD). We characterized and compared distinctive cerebrospinal fluid (CSF)-derived EVs in PD and atypical parkinsonisms (AP), aiming to integrate a diagnostic model based on immune profiling of plasma-derived EVs via artificial intelligence. Plasma- and CSF-derived EVs were isolated from patients with PD, multiple system atrophy (MSA), AP with tauopathies (AP-Tau), and healthy controls.

Immune profiling of plasma-derived extracellular vesicles identifies Parkinson disease.

Objective: To develop a diagnostic model based on plasma-derived extracellular vesicle (EV) subpopulations in Parkinson disease (PD) and atypical parkinsonism (AP), we applied an innovative flow cytometric multiplex bead-based platform.

Methods: Plasma-derived EVs were isolated from PD, matched healthy controls, multiple system atrophy (MSA), and AP with tauopathies (AP-Tau). The expression levels of 37 EV surface markers were measured by flow cytometry and correlated with clinical scales.

Targeting Alpha Synuclein Aggregates in Cutaneous Peripheral Nerve Fibers by Free-floating Immunofluorescence Assay.

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson's disease (PD), the diagnosis still relies only on clinical signs of motor involvement that appear later on in the disease course, when most of the dopaminergic neurons are already lost. Hence, there is a strong need for a biomarker that can identify patients at the beginning of disease or at the risk of developing it.

Transplantation of clinical-grade human neural stem cells reduces neuroinflammation, prolongs survival and delays disease progression in the SOD1 rats.

Stem cells are emerging as a therapeutic option for incurable diseases, such as Amyotrophic Lateral Sclerosis (ALS). However, critical issues are related to their origin as well as to the need to deepen our knowledge of the therapeutic actions exerted by these cells. Here, we investigate the therapeutic potential of clinical-grade human neural stem cells (hNSCs) that have been successfully used in a recently concluded phase I clinical trial for ALS patients (NCT01640067).

Cervical skin denervation associates with alpha-synuclein aggregates in Parkinson disease.

Objective: Autonomic nervous system is involved at the onset of Parkinson disease (PD), and alpha-synuclein (-Syn) and its phosphorylated form (p-Syn) have been detected in dermal autonomic nerve fibers of PD. We assessed disease specific conformation variant of -Syn immunoreactivity in cutaneous nerves and characterized skin denervation patterns in PD and atypical parkinsonism (AP).

Methods: We enrolled 49 subjects, 19 with PD, 17 age-matched healthy controls, and 13 with AP.